摘要:

THE ROYAL SOCIETY OF CHEMISTRY Journal of Materials Chemistry Scientific Advisory Editor Editorial Manager Dr. Martin R. Bryce Dr. Robert J. Parker Department of Chem ist ry The Royal Society of Chemistry University of Durham Thomas Graham House South Road Science Park Durham DHI 3LE, UK Cambridge CB4 4WF, UK Staff Editor: Mrs. Janet M. Leader Senior Assistant Editor: Mrs. S. Shah Assistant Editor: Mrs. S. Youens Editorial Secretary: Miss D. J. Halls Graphics Designer: Ms. C. Taylor-Reid Materials Chemistry Editorial Board Allan E. Underhill (Bangor) (Chairman) Peter G. Bruce (St. Andrews) John W. Goodby (Hull) Martin R. Bryce (Durham) Klaus Praefcke (Berlin) David A. Dunmur (Sheffield) Brian J. Tighe (Aston) Jean Etourneau (Bordeaux) Anthony R.West (A be rdeen ) Wendy R. Flavell (UMIST) John D. Wright (Canterbury) Robert J. Parker (Secretary) International Advisory Editorial Board K. Bechgaard (Risca, Denmark) J. S. Miller (Salt Lake City, UT, USA) J. Y. 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Kahn (Orsay, France) J. W. White (Canberra, Australia) R. McCullough (Pittsburgh, USA) R. Xu (Changchun, China) Y. Yamashita (Okazaki, Japan) Journal of Materials Chemistry (ISSN 0959-9428) is published monthly by The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF, UK.All orders accompanied with payment should be sent directly to The Royal Society of Chemistry, Turpin Distribution Services Ltd., Blackhorse Road, Letchworth, Herts SG6 lHN, UK. NB Turpin Distribution Services Ltd., distributors, is wholly owned by The Royal Society of Chemistry. 1994 Annual subscription rate EC (inc. UK) f381.00, USA $718.00, Canada f431.00 (plus GST), Rest of World f410.00. Customers should make payments by cheque in sterling payable on a UK clearing bank or in US dollars payable on a US clearing bank. Air freight and mailing in the USA by Publications Expediting Inc., 200 Meacham Avenue, Elmont, NY 11003. 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These should describe original work of high quality dealing with the synthesis, structures, properties and applications of materials, particularly those associated with advanced technology.Articles Full papers contain original scientific work that has not been published previously. However, work that has appeared in print in a short form such as a Materials Chemistry Communication is normally acceptable. Four copies of Articles includ- ing a top copy with figures etc. should be sent to The Editor, Journal of Materials Chemistry,The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF, UK.Materials Chemistry Communications Materials Chemistry Communications con- tain novel scientific work in short form and of such importance that rapid publication is warranted. The total length is normally restricted to two pages of the double-column A4 format. For a Communication consisting entirely of text and ten refer- ences, with no figures, equations or tables, this corresponds to approximately 1600 words plus an abstract of up to 40 words. However, special consideration will be given to communications with a large amount of essential diagramatic information. Submission of a Materials Chemistry Communication can be made either to The Editor, Journal of Materials Chemistry, The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF, UK, or via a member of the International Advisory Editorial Board.In the latter case, the top copy of the manuscript including any figures etc., together with the name of the person to whom the Communication is being submit- ted, should be sent simultaneously to the Editor at the Cambridge address. Authors may wish to contact the Board member to ensure that he is available to arrange review of the manuscript within reasonable time. In order to avoid delay in publication, proofs of Communications are not sent to authors unless this is specifically requested. Full details of the form of manuscripts for Articles and Materials Chemistry Communications, conditions for accept-ance etc. are given in issue number one of Journal of Materials Chemistry published in January of each year, or may be ob- tained from the Staff Editor. There is no page charge for papers pub- lished in Journal of Materials Chemistry. Fifty reprints are supplied free of charge. Any author who is publishing in Journal of Materials Chemistry is entitled to a free copy of the issue in which the paper appears.

ISSN:0959-9428    

DOI:10.1039/JM99404FX045

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

Each Issue with Subject-, Author- and Materials Indexes Additional 7 0-Volume Indexes 72 volumes per year Annual Subscription Rate: SFr 7320.00 Postageklandling: SFr 720.00 Agency Discount: 70% lSSN 0377-6883 EDITORS: Professor G.E. Murch Department of Mechancal Engineering, The University of Newcastle, NSW 2308, Australia H.Neber-Aeschbacher Scitec Publications Untermuehleweg 11 CH-6300 Zug, Switzerland Dr. Fred H. Wohlbier Trans Tech Publications Hardstrasse 13 CH-4714Aedermannsdorf Switzerland ABSTRACT EDITOR: Dr. David J. Fisher Cardiff, United Kingdom Scitec Publications Member of the Trans Tech Group of Publishers .Materials Science Solid State Physics .Engineering Untermuehleweg 11 CH-6300Zug Switzerland Fax: ++41 -42 32 52 12 E-Mail: ddf@scitec.ch DEFECTnnn DlFFUrlOn The International Journal of the Defect Solid State Pt.A of Diffusion and Defect Data efect and Diffusion Forum is an international journal serving the advanced materials research community as a permanent record of significant developments in the general area of the defect solid state. Started in 1967 as Diffusion Data, the material pre- sented today encompasses the well-known ex-tended abstract section which has made this series a standard in its field, as well as critical reviews, data collections and original contributions. Complete spe- cial issues regularly focus on topics of current inter- est. Particular emphasis is placed on atomic and ionic transport, solid-state defect properties (both structural and electronic), radiation damage and de- fect production. In order to shorten publication time, correspondence can be sent electronically, and manuscripts can be accepted in electronic form. Distributed by: Trans Tech Publications Ltd Trottenstr. 20 / CH-8037 Zurich / Switzerland Fax: (++41) 12 72 I0 92 E-Mail: ddf@transtec h.c h Write us for: -Detailed scope of coverage -Instructions for authors -Information on further Materials Science titles

ISSN:0959-9428    

DOI:10.1039/JM99404BX047

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

ISSN 0959-9428 JMACEP 12) 1769-1932 (1994) Journal of Materials Chemistry Synthesis, structures, properties and applications of materials, particularly those associated with advanced technology CONTENTS 1769 Photoresists based on a novel photorearrangement of o-nitrobenzylic polymers A. Ajayaghosh, M. V. George and T. Yamaoka 1775 Sulfonated polyaniline films as cation insertion electrodes for battery applications. Part 1 .-Structural and electrochemical characterization C. Barbero, M. C. Miras, B. Schnyder, 0.Haas and R. Kotz 1785 Preparation and properties of stat-copoly (oxyethylene/oxypropylene)-LiClO, polymer electrolytes M. Nekoomanesh H., D. J. Wilson, C. Booth and J. R. Owen 1793 Comparative kinetic analyses for epoxy resins cured with imidazole-metal complexes G.J. Buist, I. Hamerton, B. J. Howlin, J. R. Jones, S. Liu and J. M. Barton 1799 Polypyrrole-poly(epich1orohydrin-co-ethyleneoxide) blend: An electroactive, electrochromic and elastomeric material M-A. De Paoli and D. J. Maia 1805 Electrochemistry of poly( 3-thiopheneacetic acid) in aqueous solution: Evidence for an intramolecular chemical reaction P. N. Bartlett and D. H. Dawson 181 1 Polyaniline alloys with poly( 3-sulfonato-4-hydroxystyrene) M. Inoue, F. Medrano, M. Nakamura, M. B. Inoue and Q. Fernando 1815 Chemical vapour deposition of ZrO, thin films monitored by IR spectroscopy B. J. Gould, I. M. Povey, M. E. Pemble and W. R. Flavell 1821 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD. Part 1.-Effect on growth rate M.L. Hitchman, J. Zhao and S. H. Shamlian 1827 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD. Part 2.-Effect on crystallinity M. L. Hitchman, J. Zhao and S. H. Shamlian 1835 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD. Part 3.-Effect on composition M. L. Hitchman, J. Zhao, S. H. Shamlian, S. Affrossman, M. Hartshorne, E. A. Maydell and H. Kheyrandish 1843 Bonded hydrogen in silicon nitride films deposited by remote plasma-enhanced chemical vapour deposition S. E. Alexandrov, M. L. Hitchman and S. H. Shamlian 1849 A new synthetic route to hydroxyapatite coatings G. Spoto, E. Ciliberto and G. C. Allen 1851 2-Amino-5-nitropyridinium acetophosphonate: A deliberately engineered non-linear optical crystal J.Pkaut and R.Masse 1855 Relaxation behaviour of NLO chromophores grafted in hybrid sol-gel matrices B. Lebeau, J. Maquet, C. Sanchez, E. Toussaere, R.Hierle and J. Zyss 1861 Synthesis, physical properties and X-ray crystal structures of a series of nickel complexes based on n-alkylthio-substituted ethylene- 1.2-dithiolene ligands A. Charlton, C. A. S. Hill, A. E. Underhill, K. M. A. Malik, M. B. Hursthouse, A. I. Karaulov and J. eller 1867 Synthesis, crystal structure and properties of [Sr,Cu(C,O,),(H,O),]: Precursor of Sr,CuO, oxide M. Insausti, M. K. Trtiaga, R. CortCs, J. L. Mesa, M. I. Arriortua and T. Rojo 1871 Phase diagram of the Bi-Sr-Cu-0 system E. Yu Vstavskaya, V. A.Cherepanov, A. Yu. Zuev, S. D. Sutton and J. S. Abell 1875 Wet chemical syntheses of ultrafine multicomponent ceramic powders through gel to crystallite conversion P. Padmhi and T. R. N. Kutty 1883 Accommodation of the misfit strain energy in the BaO( 100)/MgO( 100) heteroepitaxial ceramic interface using computer simlulation techniques D. C. Sayle, S. C. Parker and J. H. Harding 1889 Two new diphosphates with SrV,(P,O,), structure: Mercury and lead phases S. Boudin, A. Grandin, A. Leclaire, M. M. Bore1 and B. Raveau 1893 Crystal structure of U,Pt,Sn: A new derivative of the tetragonal U,Si,-type structure P. Gravereau, F. Mirambet, B. Ckvalier, F. Weill, L. Fournks, D. Laffargue, F. BourCe and J. Etourneau 1897 Synthesis and catalytic properties of magnesia fine powders prepared by microwave cold plasma heating I(.Sugiyama, Y.Nakano, H. Souri, E. Konuma and T. Matsuda 1903 Microwave-hydrothermal processing for synthesis of layered and network phosphates S. Komarneni, Q. Hua Li and R. Roy 1907 Photoisomerization of indolinespirobenzopyran in anionic clay matrices of layered double hydroxides H. Tagaya, S. Sato, T. Kuwahara, J-i. Kadokawa, K. Masa and K. Chiba 1913 Investigations of structure and protonic conductivity in the so-called tin zeolites G. B. Hix, R. C. T. Slade, K. C. Molloy and B. Ducourant 1921 Investigations of structure and protonic conductivity in composites of hydrous antimony(v) oxide and mordenite G. B. Hix, R. C. T. Slade and B. Ducourant MATERIALS CHEMISTRY COMMUNICATIONS 1927 Behaviour of ceria under hydrogen treatment: Thermogravimetry and in situ X-ray diffraction study C.Lamonier, G. Wrobel and J. P. Bonnelle 1929 Corrigendum to Novel aromatic poly(ether ketone)s. Part 3.-Synthesis of diamine precursors with 4-8 benzene rings linked by ether, ketone and sulfone groups A. J. Lawson, P. L. Pauson, D. C. Sherrington, S. M. Young and (in part) N. O’Brien 1931 Book Reviews: J. T. Guthrie; A. J. Masters; P. T. McGrail i Cumulative Author Index iv Subject Index 1994 xxi Conference Diary Note: Where an asterisk appears against the name of one or more authors, it is included with the authors’ approval to indicate that correspondence may be addressed to this person. COPIES OF CITED ARTICLES The Royal Society of Chemistry Library can usually supply copies of cited articles. For further details contact: The Library, Royal Society of Chemistry, Burlington House, Piccadilly, London W1V OBN, UK. Tel: +44 (0)71-437 8656, Fax: +44 (0)71-287 9798, Telecom Gold 84: BUR210, Electronic Mailbox (Internet) LIBRARY@RSC.ORG. If the material is not available from the Society’s Library, the staff will be pleased to advise on its availability from other sources. Please note that copies are not available from the RSC at Thomas Graham House, Cambridge.

ISSN:0959-9428    

DOI:10.1039/JM99404FP109

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

Cumulative Author Index Aarik J.. 1239 Abell J. S.. 1871 Abraham F.. 1763 Abrahams I.. 185, 775 Abser M. N.. 1173, 1765 Afanasiev P.. 1653 Affrossman S., 1835 Agullo J. M.. 695 Ahmet M. T., 1201 Ahn S-K., 949 Aidla A,, 1239 Ainslie B. J., 1233 Airoldi C.. 1479 Bedioui F., 1215 Bedson J., 571 Beguin F., 669 Bell R. G., 781 Bellwood M., 1173, 1765 Benzi P., 1067 Bertoncello R., 407 Beveridge M., 119 Bigi S., 361 Bignozzi M. C., 429 Billingham N. C., 1508 Bjerrnholm T., 675 Blasse G., 1349 Cherepanov V. A., 1871 Chernyaev S. V., 1107 Chevalier B., 463, 1893 Chiba K., 551, 1907 Chiellini E., 429, 437 Chisem I. C., 1737 Choisnet J., 895 Chu P., 719 Ciacchi F. T., 257 Ciliberto E., 1849 Clegg W., 891 Colbourn E. A., 805 Choy J-H., 1271 Fabretti A,, 1047 Facchin B., 1255 Faguy P.W., 771 Fahey J. T., 1533 Fau-Canillac F., 695 Feast W. J., 1159 Feng S., 985 Fernandez J. M., 1 I17 Fernando Q., 1811 Ferraro F., 1047 Fettis G. C., 1157, 1357 Fisher G. A., 891 Fitzmaurice J. C., 285 Haas O., 1775 Hall P. G., 1309 Hamerton I.. 379, 385, 1793 Hamstra M. A,, 1.;49 Han Y-S., 1271 Hannington J., 86'4 Harding J. H., 1883 Harris F. W., 105 Harris K. D. M., ?5, 1731 Harris S. J., 145, 217 Harrison W. T. A,, 11 11 Hartshorne M.. 1535 Haslam S. D., 209 1205 Ajayaghosh ,4., 1769 Aka G., 907 Akhtar M. J., 1081 Akhtar Z.-u.-N., 1081 Akimoto H., 61 Bonanos N., 899 Bonardi A., 713 Bond S. E., 23 Bonnelle J. P., 1927 Booth C., 591, 1507, 1785 Cole-Hamilton D. J., Coles G. S. V., 23 Coles H., 869 Colque S., 1343 Connell J. E., 399 657 Fitzmaurice, J.C., 1603 Fitzpatrick A. D., 1055 Flavell W. R., 1815 Fleming R. J., 87 Fletcher J. G., 1303 Hastie G. P., 977 Hatayama F., 205. 775 Hayashi A., 915 Heath K. D., 825 Heath R. J., 487, 633 Aksay 1. A,, 353 Alagna L., 943 Alexandrov S. E., Ali-Adib Z., 1 1843 Booth C. J., 747 Bore1 M. M., 1889 Botto L. I., 541, 1641 Boudin S., 1889 Conroy M., 1 Conway L. J., 337 Cook M. J., 209, 1205 Cook S. L., 81 Flint S. D., 509 Folkerts H. F., 1349 Forsyth M., 1149 Foster D. F., 657 Hector A. L., 279 Heinrich B., 679 Henshaw G. S., 1427 Hentrich F., 1547 Aliev A. E., 35 Allan N. L., 817 Allen G. C., 1849 A1 Raihani H., 1331 Alves 0. L., 389, 529 An Y., 985 Ando M., 631 Andreani F., 1035 Angeloni A. S., 429, 437 Angeloni L., 1047 Annila A., 585 Aoki H., 1497 ap Kendrick D., 399 Ara K., 551 Bouree F., 1893 Bowden K., 1201 Bradley R.H., 487, 1157, Branitsky G. A., 373 Branton P. J., 1309 Braybrook J. H., 1157, 1357 Brewis D. M., 487, 683 Breysse M., 1653 Brisdon B. J., 1387 Britt S., 161 Brock T., 229 Brodsky C. J., 651 Brown T., 771 1189 Cooney R. P., 557 Copplestone F. A., 421 Corriu R. J. P., 987 Cortks R., 1867 Costa Bizzarri P., 1035 Costa F. M. A., 515 Cotter J. P., 1603 Cox P. A., 805 Craig A. A,, 1705 Craig S. R., 977 Crayston J. A., 1093 Crespin M., 895 Critchlow G. W., 1245, 1249, 1591 Fournks L., 1893 Fragala I. L., 1061 Fraoua K., 305 Freakley P. K., 1189 Frechet J. M. J., 1533 Frederiksen P., 675 Friend R. H., 1227 Frialova M., 271 Fuflyigin V. N., 1585 Fujii T., 635 Fujimoto T., 61, 533, 537 Fujita T., 955 Fujiwara Y., 1219 Fukuda A., 237,997 Hermansson L., 41 3 Herod A.J., 1451 Herrero P., 1433 Hervieu M., 1353 Heughebaert J-C., 765 Heughebaert M., ?65 Heywood B. R., 1187 Hickey E., 463 Hierle R., 1855 Higuchi A., 171 Hill C. A. S., Hinds B. J., 1061 Hirose N., 9 Hitchman M. L., 61, 1821, 1233. 1861 Arai H., Arai K., 653 275 Bruce D. W., 479, 1017 Bruce P. G., 167, 1579 Cumberbatch T. J., Dan M., 1195 1393 Funfschilling J., 1673, 1689 Gaillon L., 1215 1827, 1835, 1843 Hix G. B., 189, 19 13, 1921 Aranha N.. 529 Armelao L., 407 Armes S. P., 935 Armigliato A,, 361 Arnold Jr. F. E., 105 Bryant G. C., 209 Bryce M. R., 1719 Buchecker R., 1689 Buckley C. M., 1173, 1765 Buist G. J., 379, 385, 1793 Daolio S., 1255 Darriet B., 463 David L., 1047 Davidson I.M. T., Davies A., 113 13 Gale J. D., 781, 831, 1765 Galikova L., 265, 271 Gallagher M. J., 1359 Gallardo Amores J. M., 965, 1123 Hobson R. J., 113 Hochi K., 599 Hodby J. W., 469 Hodge P., 1, 869 Hodson A. G. W., 1387 Arriortua M. I., 1867 Aruga Katori H., 915 Asaka N., 291 Aspin I. P., 385 Attfield J. P., 475, 575 Atwood M. P., 1393 Bujanowski V. J., 1181 Bujoli B., 1319 Bulmer G., 1149 Burnell G., 1309 Busca G., 965, 1123, 1755 Bush T. S., 831, 1765 Davies M. J., 813 Davies S. R., 1719 Davis T. P., 1359 Dawson D. H., 1805 Deazle A. S., 385 De Battisti A., 1255 Galli G., 429, 437 Ganguli P., 331 Garci O., 1635 Garcia A., 3 11 Garcia-Martin S., 1307 Garcia-Martinez O., 61 1 Holmes M. C., 1173, 1765 Holmes P. A,, 365 Holmgren A,, 413 Hong L., 1041 Hopkins J., 1055 Horigome K., 150: Auld J..1245, 1249, 1591 Cabello C., 1641 Dekker J. P., 689 Gatteschi D., 319, 1047 Hosokoshi Y., 121') Auroux A,. 125 Cairns J. A,, 393 del Arc0 M., 47 Geantet C., 1653 Houlton D. J., 1245, 1249, Awaga K.. Azuma K.. 1377 139 Campelo J. M., 311 Caneschi A., 319, 1047 del Carmen Prieto M., Della Casa C., 1035 1123 Gee M. B., 337 Gellman L. J., 1427 Hourd A. C., 1591 393 Baba A,. 51 Babu G. P., 331 Babushkin O., 413 Bach S., 133, 875 Cao X., 417 Capelletti R., 7 13 Cardwell D. A., 1393 Carlino S., 99 Delmon B., 903 Dennison S., 41 Depaoli G., 407 De Paoli M-A., 1799 George A. R., 1731 George M. V., 1769 Gibb T. C., 1445, 1451 Gibson R. A. G., 393 Howard J. A. K., 1719 Howlin B. J., Hu Y., 469 Hua Li Q., 1903 379, 585, 1793 Bachir S., 139 Badwal S.P. S., 257, 1437 Carr S. W., 421 Carrazan S. R. G., 47 Deschenaux R., 679, 1351 De Stefanis A., 959 Gier T. E., 1111 Gil A., 1491 Hu bert-Pfalzgraf L. G., 1409 Badyal J. P. S., 1055 Bae M-K., 991 Carruthers B., 805 Carvalho A,, 515 Devynck J., Dhas N. A,, 1215 491 Gil-Llambias F-J., 47 Gittens G. J., 1508 Hudson M. J., Hudson S. A,, 479 99, L13, 1337 Baetzold R. C., 299 BaEier N., 133, 875 Bagshaw S. A,. 557 Baiios L., 445 Baram P. S., 817 Barber0 C., 1775 Barbieri A,, 1255 Casciola M., 1313 Cassagneau T., 189 Castellanos M., 1303 Castiglioni M., 1067 Castillo R., 903 Catlow C. R. A., 1081, 1765 781, 831, Diamond D., 145, 217 Diele S., 1547 Dissanayake M. A. K. L., Dong C., 1365 Douglas W.E., 1167 Drabik M., 265, 271 1075, 1307 Glomm B., 55 Godinho M. M., 515 Goodby J. W., 71, 747 Goodenough J. B., 1627 Gopalakrishnan J., 703 Gorbenko 0.Yu., 1585 Gormezano A,, 817 Hughes A. E., 257 Hursthouse M. B., 1861 Huxham I. M., 25.2 Ibanez A., 1101 Ibn-Elhaj M., 1351 Ichimura K., 883 Ikemoto H., 537 Barbosa L. C., 529 Barker C. P.. 1055 Causa M., 825 Cellucci F., 579 Drennan J., 245 Ducourant B., 1913, 1921 Goto T., 915 Gould B. J., 1815 Imanishi N., Imayoshi K., 19 19 Barriga C., I1 17 Bartlett P. N., 1805 Barton J. M.. 379. 385, Bashall A,, 1201 Batsanov A. S., 1719 Battaglin G.. 407 Battle P. D., 421, 641, 707, 831, 1457, 1765 Batyuk V. A,. 761 Bautista F. M., 311 Bazin D., 1101 Beagley B.. 1723 Bechgaard K., 675 1793 Cervini R., 87 Cesar C.L., 529 Chaair H., 765 Challier T., 367 Chang S-H., 1271 Charlton A., 1233, 1861 Chassagneux F., 1331 Cheetham A. K., 641, 707, Chehimi M. M., 305, 741 Chen C., 469 Chen Q., 327, 1715 Chen Z., 1619 Cheng S. Z. D., 1457 105, 719 Dunmur D. A., 747 Durand B., 1331 Eda K., 205, 775 Egdell R. G., 1647 Eguchi K., 653 Ekstrand A., 615 Eldred W. K., 305 Ellis A. M., 13 Elsegood M. R. J., 891 Endregard M., 943 Ericsson T., 1101 Erokhin Yu. Yu., 1585 Errington R. J., 891 Etourneau J., 463, 1893 Gozzi D., 579 Graboy I. E., 1585 Grandin A., 1889 Grange P., 1343 Granozzi G., 407 Gravereau P., 463, 1893 Greaves C., 931, 1463, 1469, Gregory D. H., 921 Grins J., 445, 1293 Guillon D., 679, 1359 Guo Z., 327 Guthrie J. T., 1931 Gutierrez M. P., 1303 1507 Imrie C. T., 1705 Inabe T., 1377 Inada H., 171 Inagaki M., 1475 Indira L., 1487 Inman D., 1331 Inoue M., 1811 Inoue M.B., 1811 Inoue T., 1539 Insausti M., 1867 Irvine J. T. S., 995 Ishikawa K., 997 Islam M. S., 299 Ismail H., 1189 1 Isoda S., 291 Lahti P. M., 161 Mather G. C., 1303 Newton J., 869 Ramsaran 4., 605, 1143 Isozaki T., 237, 997 Itaya A., 1539 lvanovskaya M. I., 373 lyer R. M., 1077 lzaki S.. 1581 Jacobson A. J.. 1419 Laine-Ylijoki J.. 1409 Lamble G., 1723 Lamonier C., 1927 Landee C., 161 Laus M., 429,437 Lavela P., 1413 Mathieson I, 1157 Matsuba T., 599 Matsubayashi G-e., 1325 Matsuda H., 51 Matsuda T.. 955, 1497, I897 Nguyen P., 1227 Nicholson D. G., 1723 Nicol I., 29 Nielsen K., 867 Niinisto L., 1239. 1267, 1409 Ramsden J J., 1263 Ranasingh; M.G., 1359 Ranlsv J., 867 Ratcliffe P J.. 1055 Raveau B.. 1353. 1889 Raynor J. H., 13 Jaek A.. 1239 Lawrence L. W., 571 Matsumoto M., 1377 Nishiyama I., 449, 983 Reau J. M.. 1433 James M.. 575 Lawrenson B., 393 Matsuzaki I., 853 Niwa S-i., 585, 1131 Reid M., 1149 Janes R.. 1071 Lawson A. J., 1511, 1521, Maury F., 695 Nix R. M., 1403 Renard C.. 1763 Jennings R. A,. Jimenez R., 5 931 Lea M. S., 1017 1527, 1929 Maydell E. A,, 1835 Maza-Rodriguez J., 179 Nobutou T., 1539 Nogami T., 1559 Rettig W.. 1021 Reynolds (.'. A,, 1201 Jimencz-Lopez A.. Jin-Hua C., 1041 179 Lebeau B.. 1855 Le Bideau J., 1319 McCabc R. W., McCarrick M., 1173, 1765 217 Nomura R., Nomura S., 51 171 Rhomari hl., 189 Richards 13. C., 81 Joachimi D..1021 Leclaire A.. 1889 McCormick A. V., 1749 Norman N. C.. 891 Richardson R. M.. 209. Jones A. C., 1245, 1249. Lee C. K., 525, 1441 McGhee L., 29, 119 Nowinski J. L., 1579 1205 1591 Lee G. R.. 1093 McGrail P. T., 1931 Nunes M. R., 515 Rives V.. 47. I I17 Jones D. J., Jones J. R., 189 379. 385, 1793 Lee S., 991 Lee S-I., 991 McKeown N. B., McMeekin S. G., 1153 29, 119 Nygrcn M., 615, 1275 Nykanen E., 1409 Roberts K J., 977 Robertson .A. D., 457 Jones P. J. V., 805 Lecce C. F., 393 McMurdo J., 1205 O'Brien N., 15 1 I, 1527. Robertson M. I., 29, 119 Jones W., 1737 Jouanneaux A.. 1319 Jung K.. 161 Jung W-S., 949 Kadokawa J-i.. 551, 1907 Lefebvre F., Le Goff P., le Lirzin A,. Leskela M., Letouze F., 125 133, 875 319.1047 1239, 1409 1353 McMurray H. N., 1283 McPartlin M., 1201 Meakin P., 1149 Medrano F., 1811 Meinhold R. H., 1595 O'Brien P., 565. 1249, 1611 Ogawa M., 519 Ogura D., 653 Oh-hara S., 1667 1929 Rockliffe J W., 331 RodrigueL-Castellon E., 179 Rodriguez-Reinoso F., 1137 Rojas R. hl., 611. 1433. 1635 Kaharu T., 859 Le van Mao R., 605, 1143 Mellen R. S., 421 Ohlmann A., 1021 Rojo J. M.. 1433 Kahn-Harari A., 907 Kakkar A. K., 1227 Lewis A. L., 729 Lewis J.. 1227 McndonGa M. H., 515 Merkelbach P., 615 Ohnishi K., 171 Ohta K., 61, 533, 537 Rojo T.. 1867 Romanovskaya V. V., 373 Kill P-O., 1293 Li J., 413 Mesa J. L., 1867 Ohta S., 1503 Ronfard-Hnret J-C.. 139 Kamath P. V.. 1487 Li R, 773 Metcalfe K., 331 Ohtaki M., 653 Rose R.G, 995 Kang J. S.. 747 Kang W-B.. 1571 Karasu M., 551 Li X.. 657 Lightfoot P., 167, 1579 Lim G. S., 1441 Metlin Yu. G., 1659 Michel C.. 1353 Milburn G. H. W., 1767 Oki K., 635 Okuno T., 1377 Oliver S. N., 1233 Ross A,, 119 Rossignol S., 1433 Rothlisbcrper U.. 793 Karaulov A. l., 1861 Linda11 C. M., 657 Miles D. A,, 1205 Olivera-Pastor P., 179 Rourke J. f'., 1017 Kareiva A., 1267 Lindback T., 413 Miller J. D., 729 Osterlund R., 615 Rowatt B.. 253 Karppinen M., 1267 Kassabov S.. 153 Lindgren M., 223 Lindqvist 0.. 1101 Miller J. R., Mills G. P., 1201 13 Overend A. S., 1167 Owen J. R., 591, 1785 Rowley A T., 285 Roy R., 1903 Katn C., 519 Little F. J.. 167 Minaud S.. 1763 Pac C., 1571 Roziere .I..189 Kato R.. 915, 1219 Liu C-W., 393 Minelli G., 541, 1641 Padmini P., 1875 Ruiz P., 903 Katsoulis D. E., 337, 1181 Liu S., 379, 1793 Min-Hua J., 1041 Pagura C., 1255 Rushworth S. A,. 1245, Kaul A. R.. 1585 Liu-Cai F. X., 125 Mirambet F., 1893 Painter J., 11 53 1249, 1591 Kawamura I., 237 Lo Jacono M., 197 Miras M. C.. 1775 Pan W-P., 771 Russell D. K., 13 Kawara, T., 1571 Kawasaki K., 1768 Long N. J., 1227 Lopez M. L., 547 Mirtcheva E., 611 Mishima S.. 853 Pareti L., 361 Parker M. J., 1071 Ryan T. Ci.. Sadaoka 'I,., 209 663 Kelly S. M., 1673. 1689 Lorenzelli V., 965, 1755 Miura N., 631, 1259, 1581 Parker S. C., 813. 1883 S~CZ-PUC~CR.. 1307 Kennedy B. J.. 87 Kerridge D. H., 1331 Kershaw S., 1233 Loubser G., 71 Lowe J. A., 771 Lucas V., 907 Miyamae N., Miyasaka H., Mizukami F., 955 I539 585, 1131 Parkin I.P., Parsonage J. R.. 399 Partridge R. D., 1071 279, 285, 1603 Salatelli E . 1035 Sanchez C'.. 1855 Sanchez Exribano V.. 965, Khan M. S., 1227 Luna D., 311 Mohanty D. K., 623 Patil K. C., 491 1123 Kheyrandish H.. 1835 Lund A., 223, 1723 Msller J., 1861 Pauson P. L., 1511, 1521, Sano S., 175 Kijima T.. 1621 Ma W., 771 Molloy K. C., 1913 1527. 1929 Sano T.. 1131 Kim H-B., 883 MacFarlane D. R., 1149 Monk P. M. S., 1071 Payen C., 1319 Santiago .I.. 679 King T.. 1 Machida M., 1621 Montes M., 1491 Payen E., 1343 Santos M R. M. C.. 1479 Kinoshita M., 915. 1219 MacKenzie K. J. D., 1595 Morales J., 1413 Pecaut J., 1851 Sanz J..1433 Kiyozumi Y.. 585 Klein M. L.. 793 Macklin W. J.. 113 Mackrodt W. C., 817, 825 Moreau J. J. E., 987 Moretti G., 541, 1641 Pedrosa de Jesus J. D., 1611 Sastry P. V-. P. S. S., 1077 647. Klippe L., 1585 Madsen H. G., 675 Morpurgo S., 197 Pelizzi C., 713 Sato S., 1907 Klissurski D.. 153 Maeda K.. 585, 1131 Mouron P., 895 Peluau S., 1353 Sauer C., 1547 Knight K. S., 899 Maeda S., 935 Mozhaev A. P., I107 Pemble M. E., 1815 Saunders L'. R.. 825 Knowles J. C., KO E. I., 651 185, 775 Maekawa T., 1259 Mahgoub A. S., 223 Mueller J., 623 Muller W. F., 895 Peng N., 1451 Pennington M., 13 Sawa H., 915, 1219 Sawada hI., 859 Kobayashi A,. Kobayashi H., Kobayashi T.. Koch B., 903 1559 1559 291 Mai S-M., 591 Maia D. J., 1799 Maignan A., 1353 Maireles-Torres P., 179, 189 Mun M-O., 991 Munn R.W., 849 Munro D. C., 1451 Murakami, H., 1621 Peraio A,, 1313 Percec V., 719 Pereira-Ramos J-P., 875 133, Saydam S. 13 Sayle D. C.. 1883 Schnyder B., 1775 Scholten I.., 1351 Kohmoto T., 205, 775 Malandrino G., 1061 Murray K. S., 87 Perez G., 959 Schoonman J.. 689 Komarneni S., 1903 Malet P., 47 Myrvold B. O., 1667 Perez-Jimenez C., 145 Sergecv G. B.. 761 Komatsu T.. 533, 537 Malik K. M. A,, I861 Nagae S-i., 591 Petrov K., 611 Seron A., 669 Komppa V.. 585 Malik M. A., 1249 Nagase K.. 1581 Pettiti I., 541, 1641 Sessoli R.. 1047 Kondo K., 1667 Konuma E.. 1897 Kossanyi J.. 139 Malins C., 1029 Mani R.S., 623 Mann S., 1387 Naito T., 1559 Nakajima H., 1325 Nakajima T., 853 Philippot E., 1101 Pic0 C., 547 Picone P. J., 571 Shabatina T. I., 761 Shacham-Diamand Y., 1533 Shamlian S. H., 81, 1821, Kos7tics I., 1351 Kotz R., 1775 Manning R. J., Manthiram A., 1233 1627 Nakamura M., Nakamura T., 18 11 1377 Pigois-Landureau E., 741 Porta P., 197, 541, 1641 Sharma \.. 703 1827, lS35, 1843 Kouyati: D., 139 Kristo J., 1255 Maquet J., 1855 Marcos M. D., 475 Nakano H., Nakano Y., 171 1497, 1897 Porticr J., 1433 Potter F. H., 1647 Shen D.. Shen P., 105 1289 Kriitofik M., 271 Kubono K., 291 Kubranova M., 265 Kunitomo M., 205, 775 Kunou I., 955 Marder T. B., 1227 Marinas J. M., 311 Marks G., 399 Marks T. J.. 1061 Marsden J. R., 1017 Nakata Y., 1699 Nakayama C., 631 Nakayama S., 663 Nameta H., 853 Nanjundaswamy Pottgen R., 463 Povey I.M., 13, 1815 Poynter R. H., 1205 Pozarnsky G. A.. 1749 Predieri G., 361 Sheng E.. 487, 683. 1 I89 Sheridan P., I61 Sherrington D. C., 229, 253, Sherwood J. N., 977 1511, 1521. 1527. 1929 Kuramoto N.. 1195 Kuroda K., 519 Kutty T. R. N., 1875 Kuwahara T., 1907 Martin C., 1353 Martin de Vidales J. L., 1635 Martin T. L., 623 K. S., 1627 Narciso F. J., 1137 Nazar L. F., 1419 Neal G. S., 245 Pressman H. A., 501, 1313 Prosperi T., 943 Qi F., 1041 Qian Y., 1619 Shimizu A,, 1475 Shimizu I,., 1581 Shimokanatoko T., Shiomi D.. 915 51 Kuwano J., 9, 973 Labajos F. M., 11 I7 Lacey D., 1029 Laffargue D., 1893 Maruyama Y.. 1377 Masa K., 1907 Masse R., 1851 Masters A. J.. 1931 Neat R.J., 113 Nekoomanesh H. M., 1785 Netoff T. M., Neumayer D. A., 1061 1 I I I Qiu S., 735 Rahmat S., 1201 Raithby P. R., 1227 Ramis G., 1755 Shirota Y.. 171, 599 Shoji H.. 1131 Shukla A. K., 703 Silver J.. 1201 11 Simmons J. M., 1205 Suzuki Y., 237 Tomellini M., 579 Vuijk J. D., 1365 Yamaguchi A,, 1377 Simon M., 305 Svensson G., 1293 Tomkinson J., 1309 Wahl G., 1585 Yamamoto H., 635 Simpson G. S., 1508 Swindell J., 229 Tomlinson A. A. G., 943, Wakagi A., 973 Yamamoto I., 01, 533, 537 Sinclair D. C., 445 Taga T., 291 959 Wang H., 417 Yamamoto O., 19 Singh N., 509 Tagaya H., 551, 1907 Tondello E., 407 Wanklyn B. M., 469 Yamamoto T., 1539 Skakle J. M. S., 1745 Slade R. C. T., 265, 367, 501, 509, 1313, 1913, 1921 Tajbakhsh A.R., 1017 Takahashi M., 519 Takahashi S., 859 Toriumi M., 1539 Torres-Martinez L. M., 5 Toussaere E., 1855 Watanabe J., 1699 Watanabe T., 537, 1475 Watson G. W., 813 Yamaoka T., 1769 Yamazoe N., t 31, 1259, 1581 Slater P. R.. 1463. 1469 Smart S. P., 35 Smith E. G., 331 Smith J. M., 337 Smith M. E., 245 Snetivy D., 55 Soininen P., 1409 Solano Reynoso V. C., 529 Solzi M, 361 Song S-W., 1271 Sotani N., 205, 775 Souri H., 1897 Spagna A,, 437 Spoto G., 1849 Sprik M., 793 Stainton N. M., 1159 Stedman N. J., 641, 707, Stern C. L., 1061 Stucky G. D., 11 11 Styring P., 71, 1365 Su Q., 417 Suckut C., 5 Sugiyama K., 1497, 1897 1457 Takanishi Y., 997 Takano M., 19 Takatoh K., 1365 Takebe Y., 599 Takeda Y., 19 Takeuchi M., 955 Takeuchi Y., 1497 Takezoe H., 237, 997 Tamaki J., 1259 Tamura M., 915, 1219 Tan M.P., 525 Tanabe K., 853 Tanaka T., 859 Tanguy B., 1433 Tarasconi P., 713 Tateno A., 1559 Tetley L., 253 Thanapprapasr K., 591 Thanh Vu N., 1143 Thatcher J. H., 591 Thebault J., 669 Thepot P., 987 Thery J., 907 Thomas H. J., 541, 1641 Toyne K. J., 747 Tretyakov Yu. D., 1585, Trigg M. B., 245 Trindade T., 1611 Trotter J., 1201 Tschierske C., 1021, 1547 Tseung A. C. C., 1289 Tsuchida T., 631, 1503 Udagawa T., 1559 Ueda M., 883 Ueda Y., 915, 1219 Ueno T., 1539 Ulibarri M.-A., 11 17 Underhill A. E., 1233, 1861 Ungar G., 719 Urbana M. R., 311 Urtiaga M. K., 1867 Uzunova E., 153 Vaillant M., 765 van Aken P. A., 895 van der Put P. J. , 689 Van Grieken R., 499 Vancso G. J., 55 1659 Watson I. M., 1393 Watts J. F., 305 Weill F., 1893 Welford K., 1205 Weller M.T., 921 Wen J., 327, 1715 Wen-Tao Y., 1041 Wessels P. L., 71 West A. R., 5, 445, 457, 525, 647, 1075, 1303, 1307, 1441, 1745 West D., 1 Westin G., 615, 1275 Williams D. E., 1427 Williams G., 23, 1157 Williamson C. J., 565 Wilson D. J., 1785 Winfield J. M., 29, 119 Wittmann F., 1227 Wolf M., 839 Wong Chi Man M., 987 Wong K. K. W., 1387 Workman A. D., 13, 1337 Wright S. A., 1365 Yang H., 55 Yao J., 605 Yarovoy Y. K., 761 Yi L., 1755 Yogo T., 353 Yokokura H., 1667 Yokoyama A., 983 Yonehara H., 1571 Yoon Y., 719 Yoshizawa A., 449, 983 Young S. M., 1511, 1521, 1527, 1929 Yu H.. 327, 1715 Yue Y., 985 Zammit M. D., 1359 Zarbin A. J. G., 389 Zhang M., 1619 Zhang W-r., 161 Zhao J., 1821, 1827, 1835 Zhao L., 623 Zheng Q., 1041 ZhouG., 1619 Zhu Y., 1619 Sumathipala H.H., 1075, Thomas J. O., 839 Veiga M. L., 547 Wrobel G., 1927 Zhuang Z., 1041 1307 Thomas M. J. K., 399 Veringa H. J., 689 Wu Y. M., 1403 Ziemclis M. J., 1181 Sundholm F., 499 Thomson J. B., 167 Viana B., 907 Xiao F-S., 735 Zotov N., 611 Sutherland I., 487. 683, Thorne A. J., 209 Vidgeon E. A., 399 Xiao S., 605, 1143 Zuev A. Yu., 1871 Suto S., 631 1189 Thorne J. R. G., Tian M., 327 1157, 1357 Vila E., 1635 Vivien D., 907 Xu R., 735, 985 xu w., 735 Zyss J., 1855 Sutton S. D.. 1871 Tirado J. L., 1413 Volpe P., 1067 Xu Y., 985 Suzuki T.. 631 Toba M., 585, 1131 Vstavskaya E. Yu., 1871 Yakhmi J. V., 1077 ... 111 Subject Index 1994 Ab initio methods Ab initio determination of crystal structures by X-ray powder diffraction: Structure of Li,,Zr,Nb304,, 167 Acetylene Curing reactions in acetylene-terminated resins.Part 5.-Cyelotrimerization versus linear polyene formation in the catalysed cure of athynylaryl-terminated monomers, 1167 Acid-base interaction XPS investigations of acid-base interactions in adhesion. Part 4.-Use of trichloromethane as a molecular probe for the quantitative assessment of polymer basicity, 305 Determination of acid-base properties of solid materials by inverse gas chromatography at infinite dilution. A novel empirical method based on the dispersive contribution to the heat of vaporization of probes, 741 Acrylic copolymer Synthesis of high refractive index acrylic copolymers, 1359 Adhesion XPS investigations of acid-base interactions in adhesion.Part 4.-Use of trichloromethane as a molecular probe for the quantitative assessment of polymer basicity, 305 Adsorption FTIR and Raman spectroscopic investigation of 2,2'-bipyridine adsorption on silica, alumina, zirconia and titania, 557 Studies of the sorption of triethyl phosphate by ion-exchanged smectite clays, 565 Absorption4esorption properties of nitric oxide over layered cuprates, La,-,Ba,SrCu,O,, 1621 Aerogel Effect of drying temperature on the physical properties of titania aerogels, 651 Aggregation Photocontrolled aggregation of colloidal silica, 883 Aggregation control by vapour phase and heat treatments in Langmuir-Blodgett films of amphiphilic heteroarylazo dyes, 1195 Alkali metal New fluoroionophores for alkali-metal cations based on tetrameric calixarenes, 145 Alkane Investigation into the structures of some normal alkanes within the homologous series C13H28 to C60H122 using high-resolution synchrotron X-ray powder diffraction, 977 Alkoxide precursor Growth of ZnO by MOCVD using alkylzinc alkoxides as single-source precursors, 1249 Alloy Inelastic neutron scattering study of hydrogen embrittlement in titanium alloys, 1309 Alumina Solid-state reaction between molybdena and alumina: Effect of water vapour pressure on the dispersion and nature of the supported phases, 47 Mixed alumina-chromia pillared layered a-zirconium phosphate, 179 FTIR and Raman spectroscopic investigation of 2,2'-bipyridine adsorption on silica, alumina, zirconia and titania, 557 Effect of preparation methods on properties of alumina/titanias, 585 Characterization of coprecipitated Fe,O,-Al,O, powders, 1123 Effect of preparation methods on properties of amorphous alumina/silicas, 1 13 1 Catalytic activity of aluminas obtained by the thermal decomposition of mechanically ground alumina monohydrates, a-and P-Al,O,.H,O, 1503 Aluminium nitride Preparation of aluminium nitride powder from a (hydroxo)(succinato) aluminium(11) complex, 949 Investigations into the growth of A1N by MOCVD using trimethylsilylazide as nitrogen source, 1245 Investigations into the growth of AlN by MOCVD using tri-tert- butylaluminium as an alternative aluminium source, 1591 Aluminium oxochloride Preparation and characterization of encapsulated solid particles, composed of partially hydrolysed aluminium and zirconium oxochlorides, 337 Aluminogallate Optical behaviour of sodium P-aluminogallate singlt.crystals doped with Cr3 and Cr3 +-Nd3 +,907+ Aluminophosphate Structure-property relationships of some amorphou3 and crystalline aluminophosphates, 33 1 Aluminosilica te Influence of methane on the nitriding gas reduction of kaolinite, 669 Ammonium molybdenum bronze Neutron scattering investigation of hydrogenic species in the ammonium molybdenum bronze (NH4)o 24HO ,,MOO,, 501 Amorphous molecular material Photo- and electro-active amorphous molecular materials: morphology, structures, and hole transport properties of tri (biphenyl-4-yl)amine, 17 1 Amperometric oxygen sensor Amperometric PbSnF4-based oxygen sensors: rapid response at room temperature in the operating pressure range 10 kPa-7.2 MPa, 973 Amphiphilic diol derivative Bulk properties and monolayer behaviour of diol-based mesogens and their acetonides, 1021 Amphotropism Molecular design of amphotropic materials: Double- headed diol-based mesogens incorporating rigid structural units, 1547 Antiferroelectricity Devil's staircase and racemization in antiferroelectric. liquid crystals, 237 Antiferroelectric chiral smectic liquid crystals, 997 Antiferromagnetism Preparation and characterization of Sr, -.La,FeO, ( 0 6 x <l), 19 Preparation, structure and magnetic properties of a new nickel(II1) oxide: YbSr3Ni06, 575 Magneto-structural correlation in a series of iodide salts of p-N-alkylpyridinium nitronyl nitroxides: Dependence of the iodide-pyridinium ring interaction on the length c\f the N-alkyl chain, 1377 Reinterpretation of the magnetic structures of the perovskites SrFeO, and Sr,LaFe,O, 417, 1445 Antimonic acid Pyrochlore-like compounds derived from antimonic acid, 389 Antimony oxide Investigations of structure and protonic conductivit! in composites of hydrous antimony(v) oxide and mordenite, 1921 Arylethyne Mesomorphic arylethynes and their precursors, 1017 Atomic force microscopy Short-range order in extended-chain crystals of poly oxymethylene from a true molecular perspective: An atomic force microscopy study, 55 Atomic layer epitaxy In situ study of a strontium P-diketonate precursor for thin-film growth by atomic layer epitaxy, 1239 Growth of PbS thin films from novel precursors by itomic layer epitaxy, 1409 Atomistic simulation Computer modelling as a technique in materials chemistry, 781 Atomistic simulation of the surface structure of spincl, 813 Structural and defect properties of high-T, oxides determined by atomistic lattice simulation, 817 Calculated enthalpies of mixing of MnO/MgO and ViO/MgO, 825 iv Accommodation of the misfit strain energy in the Mixed oxides of SbV as catalysts for the oxidative coupling of BaO( 100)/Mg0( 100) heteroepitaxial ceramic interface using methane, 421 computer simulation techniques, 1883 Influence of preparation methods on the texture and structure of titania supported on silica, 903 Baddele yite Phases in the Zr,Ta, -x(O,N)ysystem, formed by ammonolysis of Zr-Ta gels: Preparation of a baddeleyite-type solid solution phase ZrxTal-xOl+xN1-x, O<x< 1, 1293 Barium cerate Space group and lattice constants for barium cerate and minor corrections to the crystal structures of BaCeo.9Yo.102.95 and BaCe0.9Gd0.102.95, 899 Batteries Sulfonated polyaniline films as cation insertion electrodes for battery applications.Part 1.-Structural and electrochemical characterisation, 1775 BiBr,Ph Structure of BiBr,Ph: a solid-state architecture involving secondary bonding and 71-71 interactions, 891 Bimetallic oxide Synthesis and characterization of Ni,Sb,(OEt)l, and its hydrolysis products, 1275 Binary oxide Self-consistent interatomic potentials for the simulation of binary and ternary oxides, 83 1 Preliminary crystal structure of mixed-valency Sr,Ni,O,, the actual formula of the so-called Sr,Ni,O,,, 1763 Biomaterial Effects of sintering conditions on hydroxyapatite for use in medical applications: A powder diffraction study, 185 Statistical analysis of apatitic tricalcium phosphate preparation, Bismuth vanadate Phase diagrams and stoichiometries of the solid electrolytes, Bi,V2Ol1: M, M = Co, Cu, Zn, Ca, Sr, 1441 Block copolymer Synthesis and characterization of poly(ary1 ether-sulfone) and poly( tetrahydrofuran) (A-B)N block copolymers, 623 Bronzes Investigation of the oxidation of Na,W03 surfaces, 1647 Cadmium sulfide Dopant and impurity effects in electrodeposited CdS/CdTe thin films for photovoltaic applications, 41 Cadmium telluride Chemomechanical polishing of gallium arsenide and cadmium telluride to subnanometre surface finish.Evaluation of the action and effectiveness of hydrogen peroxide, sodium hypochlorite and dibromine as reagents, 29 Dopant and impurity effects in electrodeposited CdS/CdTe thin films for photovoltaic applications, 41 Cage-type lattice Selective clathration in a cage-type host lattice of cyclophosphazene, 29 1 Calcite Polymer-mediated crystallisation of inorganic solids: Calcite nucleation on the surfaces of inorganic polymers, 1387 Calixarene New fluoroionophores for alkali-metal cations based on tetrameric calixarenes, 145 Assessment of a chromogenic calixC4) arene for the rapid colorimetric detection of trimethylamine, 217 Carbon black Interfacial chemistry and mechanical effects of a multifunctional processing additive on carbon black filled rubber, 1189 Carbothermal reduction Solid-state NMR examination of the formation of p-sialon by carbothermal reduction and nitridation of halloysite clay, 245 Preparation of aluminium nitride powder from a (hydroxo)(succinato)aluminium(n)complex, 949 Catalyst Solid-state reaction between molybdena and alumina: Effect of water vapour pressure on the dispersion and nature of the supported phases, 47 Chromium-aluminium orthophosphates.Part 1.-Structure, texture, surface acidity and catalytic activity in cyclohexene skeletal isomerization and cumene conversion of CrP0,-AlPO, catalysts, 31 1 Solid-state and surface chemistry of CuO-TiO, (anatasc) powders, 965 Catalytic activity Catalytic activity of aluminas obtained by the thermal decomposition of mechanically ground alumina monl,>hydrates, sr-and P-Al,O,.H,O, 1503 Cation exchange Modified zeolites for the removal of calcium and magnesium from hard water, 1143 Cationic complex Ion exchange of ruthenium cationic complexes by sr-tin IIV) bismonohydrogenphosphate, 1337 Cellulose Preparation of cellulose 2-methylstilbene-5-carboxylateand photoregulation of its properties, 275 Ceramics Phase formation and electrical properties in the system BaO-Li,O-TiO,, 5 Ion-exchange properties of NASICON-type phosphates with the frameworks [Ti, (PO,),] and [Til,7A10,3(PO,),], 9 Preparation and characterization of Sr,-,La,FeO, (06 x d I), 19 Controlled combustion synthesis and properties of fine-particle NASICON materials, 491 AC and DC electrochemical investigation of protonic conduction in calcium-doped barium cerate ceramics, 509 Preparation of ZnO-based varistors by the sol-gel technique, 61 5 Co-pyrolysis of hydrocarbons and SiEt, for the synthesis of graduated Si,C1 -x ceramic thin films by chemical vapour deposition, 695 Chemical routes for preparation of oxide high-temperat ure superconducting powders and precursors for superconductive ceramics, coatings and composites, 1659 Wet chemical syntheses of ultrafine multicomponent ceramic powders through gel to crystalline conversion, 1875 Accommodation of the misfit strain energy in the BaO( 100)/Mg0( 100) heteroepitaxial ceramic interface using computer simulation techniques, 1883 Ceria Behaviour of ceria under hydrogen treatment: Thermogravimetry and in situ X-ray diffraction study, 1927 Chemical derivatisation Studies of vapour-phase chemical derivatisation for XPS analysis using model polymers, 683 Chemical vapour deposition Metal-organic chemical vapour deposition of YBCO using a new, stable and volatile barium precursor, 81 Co-pyrolysis of hydrocarbons and SiEt, for the synthesis of graduated Si,C1 -,ceramic thin films by chemical vapour deposition, 695 Plasma-enhanced chemical vapour deposition of TiO,/polymer composite layers, 1055 Synthesis, characterization and crystal structure of a new thermally stable and volatile precursor [bis( 1,1,1,2,2,3,3,7,7,8,8,9,9,9-tetradecafluorononane-4,~-dionato),-tetraglyme] barium(r1) for MOCVD application, 1061 a-GeC precursors obtained by radiolysis of GeH,-hydrocarbon mixtures, 1067 Investigations into the growth of A1N by MOCVD using trimethylsilylazide as nitrogen source, 1245 Growth of ZnO by MOCVD using alkylzinc alkoxides ‘is single-source precursors, 1249 MOCVD of high-quality YBa,Cu,O, -6 films: in situ preparation of fluorine-free layers from a fluorinated barium source, 1393 Growth of TiO, overlayers by chemical vapour deposition on a single-crystal copper substrate, 1403 YBCO and BSCCO thin films prepared by wet MOCVD, 1585 Investigations into the growth of AlN by MOCVD using tri-tert- butylaluminium as an alternative aluminium source, 1 591 Chemical vapour deposition of ZrO, thin films monitored by IR spectroscopy, 18 15 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD.Part 1.-Effect on growth rate, 1821 Studies of the effects of NF, on the growth of polysilicoii films by low-pressure CVD. Part 2.-Effect on crystallinity, 16 27 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD.Part 3.-Ef€ect on composition, 1x35 V Bonded hydrogen in silicon nitride films deposited by remote Chemical routes for preparation of oxide high-temperature plasma-enhanced chemical vapour deposition, 1843 superconducting powders and precursors for superconductive A new synthetic route to hydroxyapatite coatings, 1849 ceramics, coatings and composites, 1659 Chemisorption Composite materials based on Ti and Ru oxides, 373 Synthesis, characterization, chemisorption and thermodynamic Computer simulation data of urea immobilized on silica, 1479 Competing interactions in self-assembled monolayers containing Chemomechanical polishing peptide groups: molecular dynamics studies of long-chain Chemomechanical polishing of gallium arsenide and cadmium perfluoro mercaptans on Au( 11 l), 793 telluride to subnanometre surface finish.Evaluation of the Accommodation of the misfit strain energy in the action and effectiveness of hydrogen peroxide, sodium BaO( 100)/Mg0( 100) heteroepitaxial ceramic intcrface using hypochlorite and dibromine as reagents, 29 computer simulation techniques, 1883 Chemomechanical polishing of lithium niobate using alkaline Conducting polymer silica sol and alkaline silica sol modified with Physical properties of polypyrrole films containing hydrogendifluoride anion, 119 dicyanoaurate(1) anions, PPy-Au(CN),, 87 Chirality Synthesis of a new family of comb polymers with side-chain esters Helix inversion in the chiral nematic phase of a ferroelectric and ionic conductivities of their films containing lithium liquid crystal containing a single chiral centre, 71 trifluoromethane sulfonate, 599 Mesophasic helical structures with high twisting power in Conducting polymer-clay composites for electrochemical optically active 3-methyladipic acid bis esters, 449 applications, 771 Effect of the position of lateral fluoro substituents on the phase Characterization of poly(3-hexanoyloxyethyl-2,5-thienylene)behaviour and ferroelectric properties of chiral 1-synthesized under different conditions: A comparative study, methylheptyl4'-[( 2-or 3-fluoro-4- 1035tetradecylox yphen yl) pro pi010 yloxy] biphenyl-4-carboxylates, Polypyrrole-poly (epichlorohydrin-co-ethylene oxide) blend: An 747 electroactive, electrochromic and elastomeric material, 1799 Inversion of chirality-dependent properties in helical liquid Electrochemistry of poly( 3-thiopheneacetic acid) in aqueous crystals: effects of structural modification, 1365 Synthesis, transition temperatures, some physical properties and solution: Evidence for an intramolecular chemical reaction, 1805the influence of linkages, outboard dipoles and double bonds Polyaniline alloys with poly( 3-sulfonato-4-hydroxystyrene), 181 1 on smectic C formation in cyclohexylphenylpyrimidines, 1673 Copolyimidea-Fluoro esters incorporating a cyclohexane ring: some new chiral dopants for ferroelectric mixtures, 1689 Pre-tilt angles as a function of polyimide composition for Cholesteryl ester copolyimides, 1667 Gelation of silicone fluids using cholesteryl esters as gelators, Copolymer 1181 Synthesis of high refractive index acrylic copolymers, 1359 Chromia Pre-tilt angles as a function of polyimide composition for Mixed alumina-chromia pillared layered a-zirconium phosphate, copolyimides, 1667 179 Preparation and properties of stat-copoly(oxyethylene/ Chromium-aluminium orthophosphate oxypropy1ene)-LiC10, polymer electrolytes, 1785 Chromium-aluminium orthophosphates.Part 1.-Structure, Corrosion texture, surface acidity and catalytic activity in cyclohexene Hydrothermal modification of electrocatalytic and corrosion skeletal isomerization and cumene conversion of CrP0,-AlPO, properties in nanosize particles of ruthenium dioxide hydrate, catalysts, 31 1 1283 Clathration Crosslinking Selective clathration in a cage-type host lattice of Curing reactions in acetylene-terminated resins.Part 5.-cyclophosphazene, 291 Cyelotrimerization uersus linear polyene formation in Clay the catalysed cure of athynylaryl-terminated monomers, Conducting polymer-clay composites for electrochemical 1167 applications, 771 A new single-layer plasma-developable photoresist using the Pillared layered structures us. zeolites as sorbents and catalysts. catalysed crosslinking of poly(4-hydroxystyrene1 cia Part 1.-Hydrocarbon separations on two alumina-pillared photogenerated acid, 1533 clays and an a-tin phosphate analogue, 959 Crystal growth Preparation and thermal stability of manganese-containing hy drotalcite, cMg,.7~Mn",.~4Mn"',.21 (OH)z I(C0, )o.11 -nH,Q Selection of appropriate systems for flux growth of single-crystal YBa,Cu,07-,, 469 1117 CrystallisationSynthesis of ,/I-SiAlON from clays: Effect of starting materials, Polymer-mediated crystallisation of inorganic solids: Calcite 1137 nucleation on the surfaces of inorganic polymers. 1387 Photoisomerization of indolinespirobenzopyran in anionic clay Crystallographic orientation matrices of layered double hydroxides, 1907 Single-crystal study of topotactic changes between NH,VO, andCoating Chemical routes for preparation of oxide high-temperature V205, 1475 superconducting powders and precursors for superconductive Crystal structure ceramics, coatings and composites, 1659 Ab initio determination of crystal structures by X-ray powder Colloid diffraction: Structure of Li,,Zr,Nb,O,,, 167 Photocontrolled aggregation of colloidal silica, 883 Photo- and electro-active amorphous molecular materials: Preparation and characterisation of novel polypyrrole-silica morphology, structures, and hole transport properties of tri( biphenyl-4-yl)amine, 171 colloidal nanocomposites, 935 Synthesis and crystal structure of Li,NaTa,O,,, 445Colorimetry Assessment of a chromogenic calix [41 arene for the rapid Cation ordering in distorted perovskites (MLa)( MgTe)O,, colorimetric detection of trimethylamine, 217 M =Na, K, 547 Complex impedance spectroscopy Crystal structures of two sodium yttrium molybdates: Ge-doped bismuth vanadate solid electrolytes: synthesis, phase NaY (MOO,), and Na,Y (MOO,),, 707 diagram and electrical properties, 525 Crystal structure of the high-temperature protonic conductor AC and DC electrochemical investigation of protonic conduction SrCeO,, 867 in calcium-doped barium cerate ceramics, 509 Structure of BiBr,Ph: a solid-state architecture involving Complexing agent secondary bonding and 71-71 interactions, 891 Effect of preparation methods on properties of alumina/titanias, Optical behaviour of sodium P-aluminogallate single crystals 585 doped with Cr3+ and Cr3+-Nd3+, 907 Composite Non-linear optical properties of DMIT derivatives, 1041 Conducting polymer-clay composites for electrochemical Crystal structures, magnetic and non-linear optical properties of applications, 771 methoxyphenyl nitronyl-nitroxide radicals, 1047 vi Synthesis, characterization and crystal structure of a new thermally stable and volatile precursor [bis( 1,1,1,2,2,3,3,7,7,8,8,9,9,9-tetradecafluorononane-4,6-dionato),-tetraglyme] barium@) for MOCVD application, 1061 Zinc dimethyl phosphate, Zn [O,P(OCH,),], , a one-dimensional inorganic polymer, 11 11 Electrochromic behaviour and X-ray structure analysis of a Pechmann dye, (E)-5,5’-diphenyl-3,3’-bifuranylidene-2,2’-dione, 1201 Synthesis and characterization of Ni,Sb,(OEt),, and its hydrolysis products, 1275 Novel structural arrangement for divalent metal phosphonates: synthesis of tert-butylphosphonates and structure of Co[(CO,)CPO,]-H,O, 1319 Magneto-structural correlation in a series of iodide salts of p-N-alkylpyridinium nitronyl nitroxides: Dependence of the iodide-pyridinium ring interaction on the length of the N-alkyl chain, 1377 YMoO, revisited: The crystal structure of Y,Mo,O,,, 1457 Single-crystal study of topotactic changes between NH,VO, and V,05, 1475 Crystal structures and electrical properties of the radical salts of the unsymmetrical donor EOTT (4,5-ethylenedithio-4’,5’-(2-oxatrimethylenedithio)tetrathiafulvalene), 1559 Synthesis and second-harmonic generation properties of 2-( 4- nitroanilino)-1,3,5-triazinederivatives, 1571 Structure of LiN(CF,SO,),, a novel salt for electrochemistry, 1579 X-Ray crystal structure and solid-state properties of a 1 : 1 complex of tetrathiafulvalene (TTF) and l-oxo-2,6-dimethyl-4- dicyanomethylenecyclohexa-2,5-diene,17 19 Preliminary crystal structure of mixed-valency Sr,Ni,Og, the actual formula of the so-called Sr,Ni,O,,, 1763 2-Amino-5-nitropyridinium acetophosphonate: A deliberately engineered non-linear optical crystal, 185 1 Synthesis, physical properties and X-ray crystal structures of a series of nickel complexes based on n-alkylthio-substituted ethylene- 1,2-dithiolene ligands, 186 1 Synthesis, crystal structure and properties of [S~,CU(C,O~)~(H20),]: Precursor of Sr,CuO, oxide, 1867 Two new diphosphates with SrV2( P,O,), structure: Mercury and lead phases, 1889 Crystal structure of U,Pt,Sn: A new derivative of the tetragonal U,Si,-type structure, 1893 Cyclic voltammetry Cyclic voltammetry of zeolite-supported manganese porphyrins, 121s C yclophosphazene Selective clathration in a cage-type host lattice of cyclophosphazene, 29 1 Defect Studies of model macroscopic-defect-free materials.Part 1.- Investigations of the system 4Ca0 -Al,03 * Fe20,-4Ca0 3A1,03 * SO,-hpmc-H,O by X-ray thermoanalytical and NMR techniques, 265 Studies of model macroscopic-defect-free materials. Part 2.- Microstructure and open porosity in the system 4Ca0 *Al,O, -Fe,O, -4Ca0. 3A1,0, SO,-hpmc-H,O, 271 Structural and defect properties of high-T, oxides determined by atomistic lattice simulation, 817 Dendrimer A convergent synthesis of extended aryl ester dendrimers, 1159 Density functional theory Molecular-modelling studies of the polypropylene catalyst, 805 Deposition of films Mechanisms of pyrolysis of organometallic deposition precursors, 13 Metal-organic chemical vapour deposition of YBCO using a new, stable and volatile barium precursor, 81 High-purity WO, sol-gel coatings: Synthesis and characterization, 407 Detergent Modified zeolites for the removal of calcium and magnesium from hard water, 1143 Dielectric relaxation Synthesis of a new family of comb polymers with side-chain esters and ionic conductivities of their films containing lithium trifluoromethane sulfonate, 599 Diffusion Oxygen diffusion in YBa,Cu,O, -mixed conductors: interpretation of T-jump measurements and experiments on hysteresis of conductivity, 579 Diphosphona te Two new diphosphates with SrV,( P,O,), structure: Mercury and lead phases, 1889 Donor molecule Crystal structures and electrical properties of the radical salts of the unsymmetrical donor EOTT (4,5-ethylenedithio-4‘,5’-(2-oxatrimethylenedithio)tetrathiafulvalene), 1559 Dopant effects Dopant and impurity effects in electrodeposited CdS/CtiTe thin films for photovoltaic applications, 41 Doping Electroluminescence of Ho3 + ions in semiconducting polycrystalline zinc oxide electrodes in contact with aqueous electrolyte, 139 DyeElectroluminescence of organic thin films based on blends of polystyrene and fluorescent dyes, 675 Aggregation control by vapour phase and heat treatments in Langmuir-Blodgett films of amphiphilic heteroarylazo dyes, 1195 Electrochromic behaviour and X-ray structure analysis of a Pechmann dye, (E)-5,5’-diphenyl-3,3’-bifuranylidene-2.2‘-dione, 1201 Electret Electret behaviour of di- and tri-nuclear iron hydrazonc- hexacyanoferrate compounds studied by the thermallv stimulated depolarization current technique, 713 Electrical insulating complex X-Ray crystal structure and solid-state properties of a 1 :1 complex of tetrathiafulvalene (TTF) and 1-0xo-2,6-dimethyl-4- dicyanomethylenecyclohexa-2,5-diene,17 19 Electrical property Influence of chlorine-oxygen substitution on the electric a1 properties of some oxychloride tellurite glasses, 1433 Electroactive material Photo- and electro-active amorphous molecular materials: morphology, structures, and hole transport properties of tri( biphenyl-4-yl)amine, 17 1 Polypyrrole-poly(epich1orohydrin-co-ethyleneoxide) blend: An electroactive, electrochromic and elastomeric material 1799~ Electrochromism Chromic materials.Part 1.-Liquid-crystalline behaviour and electrochromism in bis (octakis-n- alkylphthalocyaninato)lutetium(~r~)complexes, 533 Electrochromic tungsten oxide: Doping with two or thrce other metal oxides, 1071 Electrochromic behaviour and X-ray structure analysis i>f a Pechmann dye, (E)-5,5’-diphenyl-3,3’-bifuranylidene-22’-dione, 1201 Determination of the potential limits for WO, colouratjon, 1289 Preparation of gold-dispersed vanadium oxide thin film\ by an alternate spin-coating method for electrochromic applications, 1581 Polypyrrole-poly(epich1orohydrin-co-ethyleneoxide) blend: An electroactive, electrochromic and elastomeric material, 1799 Electrode Electroluminescence of Ho3+ ions in semiconducting polycrystalline zinc oxide electrodes in contact with aqueous electrolyte, 139 Electrode kinetic behaviour Electrode kinetic behaviour of (u0.4pr0.6)02 kx/ysz/( uO 4Pr0.h)02 fx 1437 Electrode material Chemical lithium insertion into sol-gel lamellar manganese dioxide MnO,,,, -nH,O, 133 Vanadium phosphate glasses.Effect of composition on their structure and performance as cathodes in high-temperature lithium polymer-electrolyte cells, 113 Electrodeposition Dopant and impurity effects in electrodeposited CdS/CdTe thin films for photovoltaic applications, 41 Electrochromic tungsten oxide: Doping with two or three other metal oxides.1071 vii Electrogeneration of base by cathodic reduction of anions: novel Variable-temperature FTIR investigation of a laterally substituted one-step route to unary and layered double hydroxides ferroelectric liquid-crystalline benzoate, 983 (LDHs), 1487 Preparation of single-phase Pb( Mg1,3Nb2;3)03 samples utilizing Electroluminescence information from solubility relationships in the +Electroluminescence of Ho3 ions in semiconducting Pb-Mg-Nb-citric acid-H,O system, 1271 polycrystalline zinc oxide electrodes in contact with aqueous Synthesis, transition temperatures, some physical properties and electrolyte, 139 the influence of linkages, outboard dipoles and double bonds Electroluminescence of organic thin films based on blends of on smectic C formation in cyclohexylphenylpyrimidines, 1673 polystyrene and fluorescent dyes, 675 a-Fluoro esters incorporating a cyclohexane ring: some new Electron-density mapping chiral dopants for ferroelectric mixtures, 1689 Intercalation of large cluster cations in TaS,, 1419 Ferromagnetism Electron diffraction Magnetic properties and crystal structure of the p-fluorophenyl Superconductivity up to 95 K in mercury-substituted 1212 nitronyl nitroxide radical crystal: Ferromagnetic intermolecular thallium cuprates (Tl,Hg),Sr,+,,Nd,,Cu,O, 1353 interactions leading to a three-dimensional network of ground Electro-optic properties triplet dimeric molecules, 1219 Synthesis and properties of low-molar-mass liquid-crystalline Magneto-structural correlation in a series of iodide salts of siloxane derivatives, 869 p-N-alkylpyridinium nitronyl nitroxides: Dependence of the Electro-rheology iodide-pyridinium ring interaction on the length of the AT-alkyl Evaluation of electro-rheological fluids incorporating chain, 1377 liquid-crystalline materials, 1029 Fibre Encapsulation Synthesis of mullite fibre from an aluminosiloxane precursor, 353 Preparation and characterization of encapsulated solid particles, Film electrode composed of partially hydrolysed aluminium and zirconium Characterization of Ru0,-based film electrodes by secondary ion oxochlorides, 337 mass spectrometry, 1255 ENDOR Fluorescence ENDOR study of 133Cs hyperfine couplings with SO; radicals in Photochromic behaviour in the fluorescence spectra of X-irradiated piezoelectric cS2s206 single crystals, 223 1,2-bis(9-acetoxy-10-anthry1)ethanein silicate glass prepared by Epoxy resin the sol-gel method, 635 Comparative kinetic analyses for epoxy resins cured with Electroluminescence of organic thin films based on blends of imidazole-metal complexes, 1793 polystyrene and fluorescent dyes, 675 EPR spectroscopy Fluorinated liquid crystal Intermolecular magnetic interactions in 2,4,6-tri(tert- Synthesis and mesomorphic properties of 4-[( 4- buty1)phenoxy and 2,6-di(tert-butyl)-.l-tritylphenoxyradicals, cyanophenyl)acetylenyl]-2,3,5,6-tetrafluorophenyl161 4-n-alkoxybenzoates, 171 5 Preparation and characterization of imidazole-metal complexes Fluoroionophoreand evaluation of cured epoxy networks, 379 New fluoroionophores for alkali-metal cations based on Etching tetrameric calixarenes, 145 Chemomechanical polishing of gallium arsenide and cadmium Free radical telluride to subnanometre surface finish.Evaluation of the Free radical generation during thermal decomposition of action and effectiveness of hydrogen peroxide, sodium azoisobutyronitrile in nematic liquid crystal mixtures, 761 hypochlorite and dibromine as reagents, 29 FTIR spectroscopySilicon-germanium films for photomasking applications, 393 FTIR and Raman spectroscopic investigation of 2,2’-bipyridine Ethanol conversion adsorption on silica, alumina, zirconia and titania, 557 A highly active and highly selective oxide catalyst for the Variable-temperature FTIR investigation of a laterally substituted conversion of ethanol to acetone in the presence of water ferroelectric liquid-crystalline benzoate, 983 vapour, 853 EXAFS Local range order of tellurium atoms in Te0,-BaO and Gallium arsenide Te0,-BaF, glassy systems, 1101 Chemomechanical polishing of gallium arsenide and cadmium telluride to subnanometre surface finish.Evaluation of the Feature article action and effectiveness of hydrogen peroxide, sodium Computer modelling as a technique in materials chemistry, 781 hypochlorite and dibromine as reagents, 29 Antiferroelectric chiral smectic liquid crystals, 997 Gas-sensitive resistor Chemical routes for preparation of oxide high-temperature Selectivity and composition dependence of response of superconducting powders and precursors for superconductive gas-sensitive resistors.Part 1.-Propane-carbon monoxide ceramics, coatings and composites, 1659 selectivity of Ba,Fe,Nb,,-,03, (1 d x d 2), 1427 Ferrimagnetism Gas sensor Crystal structure and magnetic properties of a new ferrimagnetic H,S-sensitive thin film fabricated from hydrothermally chain containing manganese(r1) and a nitronyl-nitroxide synthesized SnO, sol, 631 radical. Magnetic ordering in Mn( hfac),NITR compounds, 3 19 Preparation of an Na,Zr,Si,PO,,-sodium aluminosilicate Studies of the spinel solid solution Co2Ru1-xFex04, 515 composite and its application as a solid-state electrochemical Ferrocene CO, gas sensor, 663 1,3-Disubstituted ferrocene-containing thermotropic liquid Gel crystals of form ($-C,H,)Fe [(q5-CsH3)-1,3-170 Nuclear magnetic resonance spectroscopy of the structural (C02C6H4C02C6H40C,H,.+ 1)21, 679 evolution of vanadium pentaoxide gels, 1749 X-Ray absorption spectroscopic study of the AlPO,-5: ferrocene Gelation inclusion compound and its thermally decomposed products, Gelation of silicone fluids using cholesteryl esters as gelators, 1723 1181 Ferrocene-containing liquid crystal Gel permeation chromatography First ferrocene-containing side-chain liquid-crystalline polymers, Kinetic and simulation studies of linear epoxy systems, 385 1351 Geranium carbide Ferroelectricity a-GeC precursors obtained by radiolysis of GeH,-hydrocarbon Helix inversion in the chiral nematic phase of a ferroelectric mixtures, 1067 liquid crystal containing a single chiral centre, 71 Germanium Effect of the position of lateral fluoro substituents on the phase Silicon-germanium films for photomasking applications, 393 behaviour and ferroelectric properties of chiral Glass l-methylheptyl4-[(2- or 3-fluoro-4- Vanadium phosphate glasses.Effect of composition on their tetradecyloxyphenyl)propiolo yloxy] biphenyl-4-carboxylates, structure and performance as cathodes in high-temperature 747 lithium polymer-electrolyte cells, 113 ... Vlll Preparation and characterization of heavy-metal oxide glasses: Bi,O,-PbO-B,O,-GeO, System, 529 Photochromic behaviour in the fluorescence spectra of 1,2-bis(9-acetoxy-10-anthry1)ethanein silicate glass prepared by the sol-gel method, 635 X-Ray absorption spectroscopic study of the binary semiconducting glass PbV,O,, 943 Grafting Influence of preparation methods on the texture and structure of titania supported on silica, 903 Hallo ysite Solid-state NMR examination of the formation of p-sialon by carbothermal reduction and nitridation of halloysite clay, 245 Heat of adsorption Synthesis, characterization, chemisorption and thermodynamic data of urea immobilized on silica, 1479 Heisenberg spin Magnetic structure of the 4,4,4,4’,5,5,5’,5’-octamethyl-2,2’-m-phenylenebis (4,5-dihydroimidazol- 1-oxyl 3-oxide) biradical: quantum spin effect of S= 1 species associated with structural change, 915 Helical liquid crystal Inversion of chirality-dependent properties in helical liquid crystals: effects of structural modification, 1365 Heteropol ymetallate Anderson-type ammonium hexamolybdotungstonickelates, 541 Bulk and surface characterization of some heteropolymolybdates and the products of their reduction and sulfidation, 1641 High-field magnetisation Magnetic structure of the 4,4,4,4‘,5,5,5’,5’-octamethyl-2,2’-m-phenylenebis( 4,5-dihydroimidazol- l-oxyl 3-oxide) biradical: quantum spin effect of S= 1 species associated with structural change, 91 5 Hybrid solid Organic-inorganic hybrid solids.Control of solid formation by intermolecular interactions: evidence for a template effect, 987 Hydrogel Kinetic and mechanistic aspects of iron@) coordination to bipyridyl-based hydrogel polymer membranes, 729 Hydrogen embrittlement Inelastic neutron scattering study of hydrogen embrittlement in titanium alloys, 1309 Hydrogen molybdenum bronze Preparation and characterization of a sodium insertion compound of hydrogen molybdenum bronze, Nao.25 (H20)y[Ho.2I Moo31 2057 Hydrogen sulfide Improvement of copper oxide-tin oxide sensor for dilute hydrogen sulfide, 1259 Hydrotalcite Preparation and thermal stability of manganese-containing hydrotalcite, [Mg0.7,Mn’10.04Mn”1,.2~(OH)Z l(co3)0.11 * nH20, 1117 Hydrothermal synthesis H,S-sensitive thin film fabricated from hydrothermally synthesized SnO, sol, 631 Hydrothermal synthesis and characterization of K3Sb3PZOI4-5H,O, 985 Hydrothermal modification of electrocatalytic and corrosion properties in nanosize particles of ruthenium dioxide hydrate, 1283 Microwave-hydrothermal processing for synthesis of layered and network phosphates, 1903 Hydrox yapatite Effects of sintering conditions on hydroxyapatite for use in medical applications: A powder diffraction study, 185 Thermal expansion of hot isostatically pressed hydroxyapatite, 413 Statistical analysis of apatitic tricalcium phosphate preparation, 765 A new synthetic route to hydroxyapatite coatings, 1849 Hydrox ycarbonate Nickel-iron hydroxide carbonate precursors in the synthesis of high-dispersity oxides, 153 Hyperfine coupling ENDOR study of 13,Cs hyperfine couplings with SO; radicals in X-irradiated piezoelectric Cs,S,O, single crystals, 223 Inclusion compound Dynamic properties of the urea molecules in x,o-dibromoalkane/urea inclusion compounds investigated by ’H NMR spectroscopy, 35 X-Ray absorption spectroscopic study of the A1P04-5: ferrocene inclusion compound and its thermally decomposed products, 1723 Properties of the guest molecules in the 1,lO-dibromodecane/urea inclusion compound: A molecular dynamics simulation study, 1731 Indium pnictide Alternative single-source precursor for growth of indium pnictide thin layers, 51 Indolinespirobenzop yran Photoisomerization of indolinespirobenzopyran in anionic clay matrices of layered double hydroxides, 1907 Infrared laser Novel use of molecular dynamics simulation in studying structure-property relationships in the solid infrared laser medium Na+-Er3+ /?“-alumina, 839 Inorganic polymer Zinc dimethyl phosphate, Zn [O,P(OCH,),], ,a one-dimensional inorganic polymer, 11 11 Polymer-mediated crystallisation of inorganic solids: Calcite nucleation on the surfaces of inorganic polymers, 138’ Insertion compound Preparation and characterization of a sodium insertion compound of hydrogen molybdenum bronze, Na0.25(H2O)y[Ho.21MoO3]3 205 Interatomic potential Self-consistent interatomic potentials for the simulation <if binary and ternary oxides, 83 1 Intercalation Nano/nanocomposite systems: In situ growth of particles and clusters of semiconductor metal sulfides in porous silica-pillared layered phosphates, 189 Nanocomposite materials: Polyaniline-intercalated layered double hydroxides, 367 Intercalation of organic compounds in the layered host lattice MOO,, 551 Intercalation of copper into layered lanthanum niobium oxides, 955 Intercalation of polymerized 3-methyl- and 3,4-dimethyl-pyrrole in the VOP04 interlayer space, 1325 Ion exchange of ruthenium cationic complexes by a-tin(iv) bismonohydrogenphosphate, 1337 Thermodynamic and kinetic properties of lithium insertion into titanium misfit layer sulfides, 1413 Intercalation of large cluster cations in TaS,, 1419 Ion-exchange properties of lithium aluminium layered double hydroxides, 1737 Inverse gas chromatography Determination of acid-base properties of solid materials by inverse gas chromatography at infinite dilution.A no\ el empirical method based on the dispersive contribution to the heat of vaporization of probes, 741 Ion exchange Ion-exchange properties of NASICON-type phosphates with the frameworks [Ti, (PO,),] and [Ti,.,Al,., (PO,),], 9 Pyrochlore-like compounds derived from antimonic acid, 389 Intercalation of organic compounds in the layered host lattice MOO,, 551 Studies of the sorption of triethyl phosphate by ion-exchanged smectite clays, 565 Ion exchange of ruthenium cationic complexes by a-tin@) bismonohydrogenphosphate, 1337 Ion-exchange properties of lithium aluminium layered double hydroxides, 1737 Ionic conductivity Phase formation and electrical properties in the system BaO-Li,O-TiO,, 5 Synthesis and crystal structure of Li,NaTa,O,,, 445 Oxygen diffusion in YB~,CU,O,-~ mixed conductors: interpretation of T-jump measurements and experimenlts on hysteresis of conductivity, 579 Synthesis of a new family of comb polymers with side-chain esters and ionic conductivities of their films containing lithium trifluoromethane sulfonate, 599 ix Preparation of an Na,Zr,Si,PO,,-sodium aluminosilicate composite and its application as a solid-state electrochemical CO, gas sensor, 663 Bi,W,-,Cu,O,-, (0.7 6~60.8):A new oxide-ion conductor, 703 New Li+-ion conductors, Li4-,,Ti1 -rS,04 based on the Li4Ti0, structure, 1075 Influence of chlorine-oxygen substitution on the electrical properties of some oxychloride tellurite glasses, 1433 Phase diagrams and stoichiometries of the solid electrolytes, Bi4V2011: M, M =Co, Cu, Zn, Ca, Sr, 1441 Ionophore Assessment of a chromogenic calix [41 arene for the rapid colorimetric detection of trimethylamine, 217 Iron oxide Characterization of coprecipitated Fe,O,-Al,O, powders, 1123 IR spectroscopy Effect of composition on the lattice parameters and thermal behaviour of nickel(11)-cobalt(r1) hydroxide nitrate solid solutions, 61 1 Electret behaviour of di- and tri-nuclear iron hydrazone- hexacyanoferrate compounds studied by the thermally stimulated depolarization current technique, 7 13 Solid-state and surface chemistry of CuO-TiO, (anatase) powders, 965 Isonitrile Liquid-crystalline palladium- and platinum-isonitrile complexes: synthesis, mesomorphic properties and molecular structure, 859 Isostatic pressing Thermal expansion of hot isostatically pressed hydroxyapatite, 413 Kaolinite Influence of methane on the nitriding gas reduction of kaolinite, 669 Kinetics Kinetic and simulation studies of linear epoxy systems, 385 Kinetic and mechanistic aspects of iron@) coordination to bipyridyl-based hydrogel polymer membranes, 729 Langmuir-Blodgett film Second-harmonic generation from thick all-polymeric Langmuir- Blodgett films prepared using polyurethanes, 1 Effect of molecular polarisability distribution on the optical properties of Langmuir-Blodgett films, 849 Aggregation control by vapour phase and heat treatments in Langmuir-Blodgett films of amphiphilic heteroarylazo dyes, 1195 Monolayer behaviour and Langmuir-Blodgett film properties of some amphiphilic phthalocyanines: Factors influencing molecular organisation within the film assembly, 1205 Langmuir monolayer Bulk properties and monolayer behaviour of diol-based mesogens and their acetonides, 1021 Lanthanide pnictide Metathesis routes to lanthanide pnictides, 285 Lanthanum niobium oxide Intercalation of copper into layered lanthanum niobium oxides, 955 Laser photolysis Laser photolytic studies on sensitizers for negative photoresists: 4,4'-Diazido-3,3'-dimethoxybiphenylin poly(methy1 methacrylate) films, 1539 Layered material Ion-exchange properties of lithium aluminium layered double hydroxides, 1737 Photoisomerization of indolinespirobenzopyran in anionic clay matrices of layered double hydroxides, 1907 Reaction of molten sebacic acid with a layered (Mg/Al) double hydroxide, 99 Preparation and thermal stability of manganese-containing Nano/nanocomposite systems: In situ growth of particles and clusters of semiconductor metal sulfides in porous silica-pillared layered phosphates, 189 Nanocomposite materials: Polyaniline-intercalated layered double hydroxides, 367 Oriented microporous film of tetramethylammonium pillared saponite, 519 Intercalation of organic compounds in the layered host lattice MOO,, 551 (BaTiO,),(Ge,Ce),Cu,O,: A new homologous series of layered cuprates containing various layers of perovskite units, 773 Structural and electrochemical properties of layered manganese dioxides in relation to their synthesis: classical and sol-gel routes, 875 Intercalation of copper into layered lanthanum niobium oxides, 955 Novel structural arrangement for divalent metal phosphonates: synthesis of tert-butylphosphonates and structure of CO[(CO3)CPO,].H,O, 1319 Thermodynamic and kinetic properties of lithium insertion into titanium misfit layer sulfides, 1413 Intercalation of large cluster cations in TaS,, 1419 Absorption-desorption properties of nitric oxide over layered cuprates, La,-,Ba,SrCu,O,, 1621 Microwave-hydrothermal processing for synthesis of layered and network phosphates, 1903 Lead tevt-butoxide precursor Growth of PbS thin films from novel precursors b! atomic layer epitaxy, 1409 Lewis-acid site Catalytic activity of aluminas obtained by the thermal decomposition of mechanically ground alumina monohydrates, a-and P-Al,O,*H,O, 1503 Liquid crystal Rod-like liquid crystals of organic transition-metal complexes.Part 4.-Optically positive uniaxial nematic phase in the bis [1-(4'-alkoxybiphenyl-4-yl)-3-allcylpropane-1.3-dionato] copper@) complexes, 61 Helix inversion in the chiral nematic phase of a ferroelectric liquid crystal containing a single chiral centre, 71 Discotic liquid-crystal behaviour of some multinuclear phthalocyanine derivatives, 209 Devil's staircase and racemization in antiferroelectric liquid crystals, 237 Novel fluorinated liquid crystals.Part 9.-Synthesis and mesomorphic properties of 4-(n-alkoxycarbonyl)phenyl4-[( 4-n- alkoxy-2,3,5,6-tetrafluorophenyl)ethynyl]benzoates, 327 Semiflexible liquid-crystalline polyesters based on twin bis(p-oxybenzoyl) units. Part 1.-Effect of spacer length on mesomorphic behaviour, 429 Semiflexible liquid-crystalline polyesters based on twin bis( p-oxybenzoyl) units. Part 2.-Effect of molar mass on mesomorphic behaviour, 437 Mesophasic helical structures with high twisting power in optically active 3-methyladipic acid bis esters, 449 Mesomorphic complexes of silver trifluoromethanesulfonate and silver dodecylsulfate with 2- and 3-fluoro-4-alkoxy-4'- stilbazoles, 479 Chromic materials.Part 1.-Liquid-crystalline behaviour and electrochromism in bis(0ctakis-n- alkylphthalocyaninato)lutetium(m) complexes, 533 Discotic liquid crystals of transition-metal complexes, 537 1,3-Disubstituted ferrocene-containing thermotropic liquid crystals of form ($-C5H5)Fe[($-C,H,)-1,3-+ I )2 1, 679 Liquid-crystalline pol yethers based on conformational isomerism. Part 33.-Thermotropic polyethers based on a mesogenic group containing rigid and flexible units: 1-(4'-hydroxybiphenyl-4-y1)-2-( 4-hydroxyphenyl)propane, 719 Effect of the position of lateral fluoro substituents on the phase behaviour and ferroelectric properties of chiral l-methylheptyl4-[( 2-or 3-fluoro-4- tetradecyloxyphenyl) propioloyloxy] biphenyl-4-carboxylates, hydrotalcite, ~~go.~5~~"o.o,~~"'o.21(~~)~l(C~3)o.ll* nH,O, 747 1117 Free radical generation during thermal decomposition of Electrogeneration of base by cathodic reduction of anions: novel azoisobutyronitrile in nematic liquid crystal mixtures, 761 one-step route to unary and layered double hydroxides Liquid-crystalline palladium- and platinum-isonitrile complexes:(LDHs), 1487 synthesis, mesomorphic properties and molecular structure, 859 Mixed alumina-chromia pillared layered a-zirconium phosphate, Synthesis and properties of low-molar-mass liquid-crystalline siloxane derivatives, 869 X Variable-temperature FTIR investigation of a laterally substituted ferroelectric liquid-crystalline benzoate, 983 Antiferroelectric chiral smectic liquid crystals, 997 Mesomorphic arylethynes and their precursors, 1017 Bulk properties and monolayer behaviour of diol-based mesogens and their acetonides, 1021 Evaluation of electro-rheological fluids incorporating liquid-crystalline materials, 1029 Lyotropic and thermotropic mesophase formation of novel tetra [oligo(ethyleneoxy)]-substituted phthalocyanines, 1153 Examination of the structural features necessary for mesophase formation with aroylhydrazinato-nickel@)and -copper@) complexes, 1173 First ferrocene-containing side-chain liquid-crystalline polymers, 1351 Inversion of chirality-dependent properties in helical liquid crystals: effects of structural modification, 1365 Molecular design of amphotropic materials: Double-headed diol-based mesogens incorporating rigid structural units, 1547 Pre-tilt angles as a function of polyimide composition for copolyimides, 1667 Synthesis, transition temperatures, some physical properties and the influence of linkages, outboard dipoles and double bonds on smectic C formation in cyclohexylphenylpyrimidines, 1673 a-Fluoro esters incorporating a cyclohexane ring: some new chiral dopants for ferroelectric mixtures, 1689 A new type of main-chain liquid-crystal polymer derived from 4’-hydroxybiphenyl-4-carboxylicacid and its smectic mesophase behaviour, 1699 Effect of spacer length on the thermal properties of side-chain liquid-crystal poly(methacrylate)s, 1705 Synthesis and mesomorphic properties of 4-[(4- cyanophenyl)acetylenyl]-2,3,5,6-tetrafluorophenyl4-n-alkoxybenzoates, 1715 Lithium chromate Synthesis and properties of a new p polymorph of Li,CrO,, 1307 Lithium insertion Thermodynamic and kinetic properties of lithium insertion into titanium misfit layer sulfides, 1413 Lithium niobate Chemomechanical polishing of lithium niobate using alkaline silica sol and alkaline silica sol modified with hydrogendifluoride anion, 119 Luminescence Red bismuth emission in alkaline-earth-metal sulfates, 1349 Magnesia Synthesis and catalytic properties of magnesia fine powders prepared by microwave cold plasma heating, 1897 Magnetic material Intermolecular magnetic interactions in 2,4,6-tri(tert- buty1)phenoxy and 2,6-di(tert-butyl)-4-tritylphenoxyradicals, 161 Preparation, structure and magnetic properties of a new nickel(II1) oxide: YbSr,NiO,, 575 Magnetic ordering Crystal structure and magnetic properties of a new ferrimagnetic chain containing manganese(i1) and a nitronyl-nitroxide radical.Magnetic ordering in Mn( hfac),NITR compounds, 3 19 Magnetic structure of the 4,4,4,4’,5,5,5’,5’-octamethyl-2,2’-m-phenylenebis( 4,5-dihydroimidazol- 1-oxyl 3-oxide) biradical: quantum spin effect of S= 1 species associated with structural change, 9 15 Magnetic properties Crystal structure and magnetic properties of a new ferrimagnetic chain containing manganese(i1) and a nitronyl-nitroxide radical.Magnetic ordering in Mn( hfac),NITR compounds, 319 Magnetic measurements and transmission electron microscopy investigations on Fe-Co ultrafine powders derived from a bimetallic carbonyl cluster, 361 Influence of ionic substitution on the magnetic behaviour of Y,Cu,O,, 417 Crystal structure of the ternary silicide U,RuSi,: A new ordered version of the hexagonal AlB,-type structure, 463 Quaternary uranium copper oxides: The structure and properties of UBa,CuO,, 475 Studies of the spinel solid solution Co2Rul-,Fe,04, 515 Anderson-type ammonium hexamolybdotungstonickelates,541 Preparation, structure and magnetic properties of a new nickel(rI1) oxide: YbSr,NiO,, 575 Crystal structures, magnetic and non-linear optical proirerties of methoxyphenyl nitronyl-nitroxide radicals, 1047 Magnetic properties and crystal structure of the p-fluorc Jphenyl nitronyl nitroxide radical crystal: Ferromagnetic intermolecular interactions leading to a three-dimensional network of ground triplet dimeric molecules, 1219 Novel structural arrangement for divalent metal phosphonates: synthesis of tert-butylphosphonates and structure of CO[( CO,)CPO,].H,O, 13 19 Magneto-structural correlation in a series of iodide salts of p-N-alkylpyridinium nitronyl nitroxides: Dependence of the iodide-pyridinium ring interaction on the length of the N-alkyl chain, 1377 Reinterpretation of the magnetic structures of the perok skites SrFeO,,,,, and Sr2LaFe308,417, 1445 Synthesis under high pressure and characterisation by hlossbauer spectroscopy of non-stoichiometric Ca,Fe,O, 12, 1451 Manganese Crystal structure and magnetic properties of a new ferrimagnetic chain containing manganese(I1) and a nitronyl-nitroxide radical.Magnetic ordering in Mn( hfac),NITR compounds, 3 19 Manganese cobaltite Thermal behaviour and reactivity of manganese cobaltites MnxCo3-,04 (0.0<x < 1.0) obtained at low temperature, 1635 Manganese dioxide Structural and electrochemical properties of layered manganese dioxides in relation to their synthesis: classical and sol-gel routes, 875 MAS NMR Studies of the sorption of triethyl phosphate by ion-excl ianged smectite clays, 565 Role of additives in the sintering of silicon nitride: A ,’Si, 27Al, ,,Mg and 89Y MAS NMR and X-ray diffraction studv, 1595 170Nuclear magnetic resonance spectroscopy of the structural evolution of vanadium pentaoxide gels, 1749 Mathematical model Oxygen diffusion in YBa,Cu,O, + ceramics, 1107 Membrane Kinetic and mechanistic aspects of iron(1i) coordination to bipyridyl-based hydrogel polymer membranes, 729 Mercury-containing superconductor Synthesis and superconducting properties of HgBa,Ca,Cu,O, +*, 99 1 Mercury intrusion method Comparison of porosity characteristics of macroporous poly(styrene-divinylbenzene) resins determined from inercury intrusion data and image analysis of transmission electron micrographs, 253 Mesogen Molecular design of amphotropic materials: Double-headed diol-based mesogens incorporating rigid structural units, 1547 Mesophase stability Bulk properties and monolayer behaviour of diol-based mesogens and their acetonides, 1021 Metal alkyl Syntheses of soluble polymeric Lewis bases and their adducts with metal alkyls, 657 Metallomesogen Liquid-crystalline palladium- and platinum-isonitrile complexes: synthesis, mesomorphic properties and molecular structure, 859 Examination of the structural features necessary for mesophase formation with aroylhydrazinato-nickel(i1)and -copper(ii) complexes, 1173 Metal-organic chemical vapour deposition Growth of ZnO by MOCVD using alkylzinc alkoxides ,is single-source precursors, 1249 Metal oxide High-speed preparation of metal oxide fine powders by microwave cold plasma heating, 1497 Role of oxoanions in the stabilization of tetragonal zirconia, 1653 Metathesis route Metathesis routes to lanthanide pnictides, 285 Micropore Effect of thermal treatment on microporous accessibility in aluminium pillared clays, 149 1 Microporous solid New route for dispersion of inorganic salts onto the channel surfaces of microporous crystals: high dispersion of C uC1, in zeolites using a microwave technique, 735 xi Microwave cold plasma heating High-speed preparation of metal oxide fine powders by microwave cold plasma heating, 1497 Synthesis and catalytic properties of magnesia fine powders prepared by microwave cold plasma heating, 1897 Microwave technique New route for dispersion of inorganic salts onto the channel surfaces of microporous crystals: high dispersion of CuCI, in zeolites using a microwave technique, 735 Microwave-hydrothermal processing for synthesis of layered and network phosphates, 1903 Misfit strain energy Accommodation of the misfit strain energy in the BaO( 100)/Mg0( 100) heteroepitaxial ceramic interface using computer simulation techniques, 1883 Mixed oxide High-temperature thermoelectric properties of In,O,-based mixed oxides and their applicability to thermoelectric power generation, 653 Characterization of coprecipitated Fe,O,-Al,O, powders, 1123 Effect of preparation methods on properties of amorphous alumina/silicas, 1 13 1 Thermal behaviour and reactivity of manganese cobaltites Mn,Co,-,O, (0.0<x <1.0) obtained at low temperature, 1635 Modified zeolite Modified zeolites for the removal of calcium and magnesium from hard water, 1143 Molecular dynamics Competing interactions in self-assembled monolayers containing peptide groups: molecular dynamics studies of long-chain perfluoro mercaptans on Au( 11 l), 793 Novel use of molecular dynamics simulation in studying structure-property relationships in the solid infrared laser medium Na+-Er3+ P"-Alumina, 839 Properties of the guest molecules in the 1,lO-dibromodecane/urea inclusion compound: A molecular dynamics simulation study, 1731 Molecular modelling Computer modelling as a technique in materials chemistry, 78 1 Competing interactions in self-assembled monolayers containing peptide groups: molecular dynamics studies of long-chain perfluoro mercaptans on Au(lll), 793 Molecular-modelling studies of the polypropylene catalyst, 805 Atomistic simulation of the surface structure of spinel, 813 Structural and defect properties of high-T, oxides determined by atomistic lattice simulation, 817 Calculated enthalpies of mixing of MnO/MgO and NiO/MgO, Self-consistent interatomic potentials for the simulation of binary and ternary oxides, 831 Novel use of molecular dynamics simulation in studying structure-property relationships in the solid infrared laser medium Na+-Er3 P"-Alumina, 839 + Effect of molecular polarisability distribution on the optical properties of Langmuir-Blodgett films, 849 Molecular polarisability Effect of molecular polarisability distribution on the optical properties of Langmuir-Blodgett films, 849 Molecular structure Photo- and electro-active amorphous molecular materials: morphology, structures, and hole transport properties of tri( biphenyl-4-yl)amine, 171 Molten salt Zirconia formation by reaction of zirconium sulfate in molten alkali-metal nitrates or nitrites, 133 1 Mol ybdena Solid-state reaction between molybdena and alumina: Effect of water vapour pressure on the dispersion and nature of the supported phases, 47 Mordenite Investigations of structure and protonic conductivity in composites of hydrous antimony(v) oxide and mordenite, 1921 Mossbauer spectroscopy Nickel-iron hydroxide carbonate precursors in the synthesis of high-dispersity oxides, 153 Synthesis under high pressure and characterisation by Mossbauer spectroscopy of non-stoichiometric Ca,Fe,O,,,,, 1451 Mullite Synthesis of mullite fibre from an aluminosiloxane precursor, 353 Multifunctional additive Interfacial chemistry and mechanical effects of a multifunctional processing additive on carbon black filled rubber.1189 Nanocomposite Nano/nanocomposite systems: In situ growth of particles and clusters of semiconductor metal sulfides in porous silica-pillared layered phosphates, 189 Nanocomposite materials: Polyaniline-intercalated layered double hydroxides, 367 Preparation and characterisation of novel polypyrrole-silica colloidal nanocomposites, 935 y-Radiation sol-gel synthesis of glass-metal nanocomposites, 1619 Nanoscale material Hydrothermal modification of electrocatalytic and corrosion properties in nanosize particles of ruthenium dioxide hydrate, 1283 Nasicon Neutron diffraction structural study of the Nasicon-related phases Li MI1 MI11 ,-,(SO4),-? (Se04)y (MI' =Mg, Ni, Zn; MI1'= Al, CG, 14x63 Powder neutron diffraction study of the Nasicon-related phases NaxM11xM1112-x(SO,), -? (SO,)? :M" =Mg, M"' =Fe, In, 1469 Natural rubber Interfacial chemistry and mechanical effects of a multifunctional processing additive on carbon black filled rubber, 1189 Negative photoresist Laser photolytic studies on sensitizers for negative photoresists: 4,4'-Diazido-3,3'-dimethoxybiphenylin poly(methy1 methacrylate) films, 1539 Neutron diffraction Space group and lattice constants for barium cerate and minor corrections to the crystal structures of BaCe,.,Y,, and BaCe0.9Gd0.102.95, 899 Neutron diffraction study of the 'doubled perovskite' phases Ba,M, -,Cu,04 + (M =In, Sc), 92 1 Neutron powder diffraction study of (Bio,35Cu,,,,)YSr,Cu,0,, 93 1 Powder neutron diffraction study of the Nasicon-related phases Na,M1l,M"l,-,(SO,),-,,(SO,),:MI1= Mg, MI1'= Fe, In, 1469 Neutron scattering Neutron scattering investigation of hydrogenic species in the ammonium molybdenum bronze (NH,),,,,H0,,3Mo0,, 501 Inelastic neutron scattering study of hydrogen embrittlement in titanium alloys, 1309 Examination of the orientation dependence of the quasielastic scattering of neutrons by pellicular zirconium phosphate film, 1313 Nickel bis(dithio1ene) Synthesis, physical properties and X-ray crystal structures of a series of nickel complexes based on n-alkylthio-substituted ethylene-1,2-dithiolene ligands, 1861 Nickel bis (dithiolene) oligomer Soluble nickel bis(dithio1ene) oligomers for third-order non-linear optical studies, 1233 Nickelocene Curing reactions in acetylene-terminated resins.Part 5.- Cyclotrimerization versus linear polyene formation in the catalysed cure of athynylaryl-terminated monomers, 1167 Niobium chloroalkoxide Sol-gel processing of niobium chloroalkoxides, 1093 Nitrate Zirconia formation by reaction of zirconium sulfate in molten alkali-metal nitrates or nitrites, 1331 Nitridation Solid-state NMR examination of the formation of p-sialon by carbothermal reduction and nitridation of halloysite clay, 245 Preparation of aluminium nitride powder from a (hydroxo)(succinato) aluminium(11) complex, 949 Synthesis of ,6-SiAlON from clays: Effect of starting materials, 1137 Nitrite Zirconia formation by reaction of zirconium sulfate in molten alkali-metal nitrates or nitrites, 1331 Nitrogen adsorption Effect of thermal treatment on microporous accessibility in aluminium pillared clays, 1491 xii Nitronyl nitroxide Crystal structures, magnetic and non-linear optical properties of methoxyphenyl nitronyl nitroxide radicals, 1047 Magnetic properties and crystal structure of the p-fluorophenyl nitronyl nitroxide radical crystal: Ferromagnetic intermolecular interactions leading to a three-dimensional network of ground triplet dimeric molecules, 1219 NMR spectroscopy Dynamic properties of the urea molecules in u,o-dibromoalkane/urea inclusion compounds investigated by ,H NMR spectroscopy, 35 Solid-state NMR examination of the formation of p-sialon by carbothermal reduction and nitridation of halloysite clay, 245 Studies of model macroscopic-defect-free materials.Part 1.- Investigations of the system 4Ca0 -A1203 Fe2O,-4CaO * 3A1,0, * SO,-hpmc-H,O by X-ray thermoanalytical and NMR techniques, 265 Studies of model macroscopic-defect-free materials.Part 2.-Microstructure and open porosity in the system 4Ca0 -A1,0, -Fe,O, -4Ca0 -3A1,0, -SO,-hpmc-H,O, 27 1 Preparation and characterization of imidazole-metal complexes and evaluation of cured epoxy networks, 379 Studies of the sorption of triethyl phosphate by ion-exchanged smectite clays, 565 Synthesis and characterization of poly(ary1 ether-sulfone) and poly( tetrahydrofuran) (A-B), block copolymers, 623 Mesomorphic arylethynes and their precursors, 1017 Characterization of poly (3-hexanoyloxyethyl-2,5-thienylene) synthesized under different conditions: A comparative study, 1035 I3C Nuclear magnetic resonance spectroscopic study of plasticization in solid polymer electrolytes, 1149 Non-linear optics Preparation and characterization of heavy-metal oxide glasses: Bi,O,-PbO-B,O,-GeO, System, 529 Non-linear optical properties of DMIT derivatives, 1041 Crystal structures, magnetic and non-linear optical properties of methoxyphenyl nitronyl nitroxide radicals, 1047 Soluble nickel bis(dithio1ene) oligomers for third-order non-linear optical studies, 1233 Synthesis and second-harmonic generation properties of 2-( 4-nitroani1ino)- 1,3,5-triazine derivatives, 1571 2-Amino-5-nitropyridinium acetophosphonate: A deliberately engineered non-linear optical crystal, 185 1 Relaxation behaviour of NLO chromophores grafted in hybrid sol-gel matrices, 1855 Non-stoichiometric oxygen Perovskite-like intergrowth structure of the reduced cuprate Nd,CuO,,,: a combination of defect and excess oxygen non-stoichiometry phenomena, 895 Nuclear waste Microwave-hydrothermal processing for synthesis of layered and network phosphates, 1903 Nucleation Polymer-mediated crystallisation of inorganic solids: Calcite nucleation on the surfaces of inorganic polymers, 1387 Olivine Synthesis of QMD and QD polyorganosiloxanes from tetrakis( trimethylsi1oxy)silane and palabora vermiculite, 399 Optical properties Optical behaviour of sodium p-aluminogallate single crystals doped with Cr3+ and Cr3+-Nd3+, 907 Optical waveguide Porosity of pyrolysed sol-gel waveguides, 1263 Organic radical Magnetic structure of the 4,4,4’,4’,5,5,5’,5’-octamethyl-2,2’-m-phenylenebis( 4,5-dihydroimidazol-l-oxyl3-oxide) biradical: quantum spin effect of S= 1 species associated with structural change, 915 Organometallic polymer Synthesis and optical spectroscopy of linear long-chain di-terminal alkynes and their Pt-o-acetylide polymeric complexes, 1227 Organometallic precursor Mechanisms of pyrolysis of organometallic deposition precursors, 13 Alternative single-source precursor for growth of indium pnictide thin layers, 51 Metal-organic chemical vapour deposition of YBCO using a new, stable and volatile barium precursor, 81 Oxide catalyst A highly active and highly selective oxide catalyst for the conversion of ethanol to acetone in the presence of w;tter vapour, 853 Oxide electrode Characterization of Ru0,-based film electrodes by secondary ion mass spectrometry, 1255 Oxygen diffusion Atomistic mechanisms of oxygen diffusion in YBa,Cu,O, -,and Y Ba,Cu,O,, 299 Oxygen diffusion in YBa2Cu,06+, ceramics, 1107 Oxygen sensor Amperometric PbSnF,-based oxygen sensors: rapid response at room temperature in the operating pressure range 10 kPa-7.2 MPa, 973 Partial cation order Li,Ni,TaO,: A novel rock salt superstructure phase witki partial cation order, 1303 Pechmann dye Electrochromic behaviour and X-ray structure analysis of a Pechmann dye, (E)-5,5’-diphenyl-3,3’-bifuranylidene-2,~’-dione, 1201 Pellicular film Examination of the orientation dependence of the quasielastic scattering of neutrons by pellicular zirconium phosphate film, 1313 Perovskite-like intergrowth Perovskite-like intergrowth structure of the reduced cuprate Nd,CuO, ,: a combination of defect and excess oxygen non-stoichiometry phenomena, 895 Perovskite structure Cation ordering in distorted perovskites (MLa)( MgTe)O,, M =Na, K, 547 (BaTiO,),(Ge,Ce),Cu,O,: A new homologous series of layered cuprates containing various layers of perovskite units, 773 Neutron diffraction study of the ‘doubled perovskite’ ph‘ises Ba,M, -,Cu,04 + (M =In, Sc), 92 1 Reinterpretation of the magnetic structures of the perovskites SrFe0,,710 and Sr,LaFe,O, 417, 1445 Phase diagram Phase diagram of the Bi-Sr-Cu-0 system, 1871 Phase equilibria Phase formation and electrical properties in the system BaO-Li,O-TiO,, 5 Polymorphism and crystal chemistry of Li, 5Gao ,GeO,, an Li,PO, analogue, 457 Ge-doped bismuth vanadate solid electrolytes: synthesis, phase diagram and electrical properties, 525 X-Ray analysis of two phases in the barium borate, sodium barium borate and sodium borate ternary phase diagr<im, 57 1 Study of the Ru-Mo-0 and Ru-W-0 phase systems; rutile solid solutions Ru, -,M,Oz, 641 Phases in the Zr,Ta, -,(O,N),, system, formed by ammoiiolysis of Zr-Ta gels: Preparation of a baddeleyite-type solid solution phase ZrxTal-xOl+xN1-x, O<x< 1, 1293 Phase transition Novel synthetic pathway to Bi( Pb)-2223 phase with varidble Ca : Sr ratio, Bi, 7Pbo ,Sr,-,Ca,Cu30, : 1.85 d x d 2.4, 647 1,3-Disubstituted ferrocene-containing thermotropic liquid crystals of form (q5-C5H,)Fe[(q5-C5H,)-1,3-(C02C6H4C02C6H40CuH2n + 1121, 679 Phosphatoantimonate Hydrothermal synthesis and characterization of K,Sb,P,O,, -5H20, 985 Phosphonate Novel structural arrangement for divalent metal phosphonates: synthesis of tert-butylphosphonates and structure of CO [(CO3)CP0,].H20, 1319 Photoactive material Photo- and electro-active amorphous molecular materials: morphology, structures, and hole transport properties of tri( biphenyl-4-yl)amine, 171 Oriented microporous film of tetramethylammonium pillared saponite, 519 ...Xlll Photochromism Photochromic behaviour in the fluorescence spectra of 1,2-bis(9-acetoxy-10-anthry1)ethanein silicate glass prepared by the sol-gel method, 635 Photocontrolled aggregation of colloidal silica, 883 Photofunctional material Preparation of cellulose 2-methylstilbene-5-carboxylate and photoregulation of its properties, 275 Photomask Silicon-germanium films for photomasking applications, 393 Photoregulation Preparation of cellulose 2-methylstilbene-5-carboxylate and photoregulation of its properties, 275 Photoresist A new single-layer plasma-developable photoresist using the catalysed crosslinking of poly( 4-hydroxystyrene) via photogenerated acid, 1533 Laser photolytic studies on sensitizers for negative photoresists: 4,4’-Diazido-3,3‘-dimethoxybiphenylin poly(methy1 methacrylate) films, 1539 Photoresists based on a novel photorearrangement of o-nitrobenzylic polymers, 1769 Phthaloc yanine Discotic liquid-crystal behaviour of some multinuclear phthalocyanine derivatives, 209 Chromic materials. Part 1.-Liquid-crystalline behaviour and electrochromism in bis(0ctakis-n- alk ylpht haloc yaninato) lutetium (111) complexes, 53 3 Discotic liquid crystals of transition-metal complexes, 537 Lyotropic and thermotropic mesophase formation of novel tetra [oligo(ethyleneoxy)]-substituted phthalocyanines, 1 153 Monolayer behaviour and Langmuir-Blodgett film properties of some amphiphilic phthalocyanines: Factors influencing molecular organisation within the film assembly, 1205 Piezoelectricity ENDOR study of 133Cs hyperfine couplings with SO; radicals in X-irradiated piezoelectric Cs,S,O, single crystals, 223 Pillared clay Effect of thermal treatment on microporous accessibility in aluminium pillared clays, 1491 Pillared material Mixed alumina-chromia pillared layered a-zirconium phosphate, Nano/nanocomposite systems: In situ growth of particles and clusters of semiconductor metal sulfides in porous silica-pillared layered phosphates, 189 Pillared hydroxycarbonates and mixed oxides.Part 1.-Copper-zinc-cobalt-aluminium system, 197 Pillared layered structures vs. zeolites as sorbents and catalysts. Part 1.-Hydrocarbon separations on two alumina-pillared clays and an a-tin phosphate analogue, 959 Plasma High-speed preparation of metal oxide fine powders by microwave cold plasma heating, 1497 Plasma-enhanced chemical vapour deposition Plasma-enhanced chemical vapour deposition of TiO,/polymer composite layers, 1055 Bonded hydrogen in silicon nitride films deposited by remote plasma-enhanced chemical vapour deposition, 1843 Polyamide Photoresists based on a novel photorearrangement of o-nitrobenzylic polymers, 1769 Polyaniline Sulfonated polyaniline films as cation insertion electrodes for battery applications.Part 1.-Structural and electrochemical characterisation, 1775 Polyaniline alloys with poly( 3-sulfonato-4-hydroxystyrene), 181 1 Poly(ary1 ether-sulfone) Synthesis and characterization of poly(ary1 ether-sulfone) and poly( tetrahydrofuran) (A-B), block copolymers, 623 Poly (ether ketone) Novel aromatic poly(ether ketone)s.Part 1.-Synthesis and thermal properties of poly(ether keto imide)s, 151 1 Novel aromatic poly(ether ketone)s. Part 2.-Synthesis and thermal properties of poly(ether keto amide)s, 1521 Novel aromatic poly(ether ketones)s. Part 3.-Synthesis of diamine precursors with 4-8 benzene rings linked by ether, ketone and sulfone groups, 1527 Corrigendum to Novel aromatic poly(ether ketonels. Part 3.- Synthesis of diamine precursors with 4-8 benzene rings linked by ether, ketone and sulfone groups, 1929 Polyethylene: Adhesion Surface studies of polyethylene modified by flame treatment, 487 Pol yimide Organo-soluble segmented rigid-rod polyimide films. Part 5.- Effect of orientation, 105 Synthesis and characterisation of porous particulate polyimides, 229 Po1ymer Surface oxidation of poly ether ether ketone using ultraviolet/ozone, 1 157 Polymer electrolyte Vanadium phosphate glasses.Effect of composition on their structure and performance as cathodes in high-temperature lithium polymer-electrolyte cells, 1 13 Effect of salt concentration on the properties of poly [oxymethylene-oligo (oxyethylene)]/Mg( C104)* polymer electrolytes, 59 1 Synthesis of a new family of comb polymers with side-chain esters and ionic conductivities of their films containing lithium trifluoromethane sulfonate, 599 I3C Nuclear magnetic resonance spectroscopic study of plasticization in solid polymer electrolytes, 1149 Structure of LiN(CF3S02),, a novel salt for electrochemistry, 1579 Preparation and properties of stat-copoly(oxyethylene/ oxypropy1ene)-LiC10, polymer electrolytes, 1785 Polymer film Electrochemistry of poly( 3-thiopheneacetic acid) in aqueous solution: Evidence for an intramolecular chemical reaction, 1805 Polymeric Lewis base Syntheses of soluble polymeric Lewis bases and their adducts with metal alkyls, 657 Polymerisation Curing reactions in acetylene-terminated resins.Part 5.- Cyclotrimerization versus linear polyene formation in the catalysed cure of athynylaryl-terminated monomers, 1 167 Intercalation of polymerized 3-methyl- and 3,4-dimethyl-pyrrole in the VOP04interlayer space, 1325 Polymer liquid crystal A new type of main-chain liquid-crystal polymer derived from 4’-hydroxybiphenyl-4-carboxylicacid and its smectic mesophase behaviour, 1699 Polymer synthesis Semiflexible liquid-crystalline polyesters based on twin bis( p-oxybenzoyl) units.Part 1.-Effect of spacer length on mesomorphic behaviour, 429 Semiflexible liquid-crystalline polyesters based on twin bis(p-oxybenzoyl) units. Part 2.-Effect of molar mass on mesomorphic behaviour, 437 Synthesis and characterization of poly(ary1 ether-sulfone) and poly (tetrahydrofuran) (A-B), block copolymers. 623 Liquid-crystalline polyethers based on conformational isomerism. Part 33.-Thermotropic polyethers based on a mesogenic group containing rigid and flexible units: 1-(4‘- hydroxybiphenyl-4-y1)-2-( 4-hydroxyphen yl )propane, 7 19 Synthesis and properties of low-molar-mass liquid-crystalline siloxane derivatives, 869 Characterization of poly( 3-hexanoyloxyethyl-2,5-thienylene) synthesized under different conditions: A comparative study, 1035 A convergent synthesis of extended aryl ester dendrimers, 1 159 Synthesis and optical spectroscopy of linear long-chain di-terminal alkynes and their Pt-o-acetylide polymeric complexes, 1227 Novel aromatic poly(ether ketone)s.Part 1.-Synthesis and thermal properties of poly(ether keto imide)s, 151 1 Novel aromatic poly(ether ketone)s. Part 2.-Synthesis and thermal properties of poly(ether keto amide)s, 1521 Novel aromatic poly(ether ketones)s. Part 3.-Synthesis of diamine precursors with 4-8 benzene rings linked by ether, ketone and sulfone groups, 1527 Corrigendum to Novel aromatic poly(ether ketone)s.Part 3.- Synthesis of diamine precursors with 4-8 benzene rings linked by ether, ketone and sulfone groups, 1929 Polyoxymeth ylene Short-range order in extended-chain crystals of polyoxymethylene from a true molecular perspective: An atomic force microscopy study, 55 xiv Poly [ox ymeth ylene-oligo (oxyeth ylene)] Effect of salt concentration on the properties of poly [oxymethylene-oligo(oxyethylene)]/Mg(C104)~polymer electrolytes, 59 1 Polypropylene Molecular-modelling studies of the polypropylene catalyst, 805 Pol ypyrrole Physical properties of polypyrrole films containing dicyanoaurate(1) anions, PPy-Au(CN),, 87 Preparation and characterisation of novel polypyrrole-silica colloidal nanocomposites, 935 Polysilicon film Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD.Part. 1.-Effect on growth rate, 1821 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD. Part 2.-Effect on crystallinity, 1827 Studies of the effects of NF, on the growth of polysilicon films by low-pressure CVD. Part 3.-Effect on composition, 1835 Polystyrene Electroluminescence of organic thin films based on blends of polystyrene and fluorescent dyes, 675 Poly (styrene-divinylbenzene) Comparison of porosity characteristics of macroporous poly (styrene-divinylbenzene) resins determined from mercury intrusion data and image analysis of transmission electron micrographs, 253 Poly (tetrahydrofuran) Synthesis and characterization of poly(ary1 ether-sulfone) and poly( tetrahydrofuran) (A-B), block copolymers, 623 Pol ythiophene Electrochemistry of poly( 3-thiopheneacetic acid) in aqueous solution: Evidence for an intramolecular chemical reaction, 1805 Polyurethane Second-harmonic generation from thick all-polymeric Langmuir- Blodgett films prepared using polyurethanes, 1 Porous material Synthesis and characterisation of porous particulate polyimides, Comparison of porosity characteristics of macroporous poly (styrenedivinylbenzene) resins determined from mercury intrusion data and image analysis of transmission electron micrographs, 253 Oriented microporous film of tetramethylammonium pillared saponite, 519 Selective removal of silicon from zeolite frameworks using sodium carbonate, 605 H,S-sensitive thin film fabricated from hydrothermally synthesized SnO, sol, 631 Porphyrin Cyclic voltammetry of zeolite-supported manganese porphyrins, 1215 Positive-tone image A new single-layer plasma-developable photoresist using the catalysed crosslinking of poly( 4-hydroxystyrene) via photogenerated acid, 1533 Powder Magnetic measurements and transmission electron microscopy investigations on Fe-Co ultrafine powders derived from a bimetallic carbonyl cluster, 361 High-speed preparation of metal oxide fine powders by microwave cold plasma heating, 1497 Wet chemical syntheses of ultrafine multicomponent ceramic powders through gel to crystalline conversion, 1875 Powder diffraction Preparation and characterization of Sr, -,La,FeO, (0< x < 1), 19 Nickel-iron hydroxide carbonate precursors in the synthesis of high-dispersity oxides, 153 Ab initio determination of crystal structures by X-ray powder diffraction: Structure of Li,9Zr,Nb,0,,, 167 Effects of sintering conditions on hydroxyapatite for use in medical applications: A powder diffraction stbdy, 185 Pillared hydroxycarbonates and mixed oxides.Part 1 .-Copper- zinc-cobalt-aluminium system, 197 Polymorphism and crystal chemistry of Li,,,Ga,,,GeO,, an Li,P04 analogue, 457 Crystal structure of the ternary silicide U,RuSi,: A new ordered version of the hexagonal AlB,-type structure, 463 Quaternary uranium copper oxides: The structure and properties of UBa,CuO,, 475 Preparation, structure and magnetic properties of a neu nickel(m) oxide: YbSr,NiO,, 575 Selective removal of silicon from zeolite frameworks using sodium carbonate, 605 Study of the Ru-Mo-0 and Ru-W-0 phase systems; riitile solid solutions Ru, -,M,O,, 641 Crystal structures of two sodium yttrium molybdates: NaY ( MOO,), and Na,Y ( MOO,),, 707 Crystal structure of the high-temperature protonic condiictor SrCeO,, 867 Perovskite-like intergrowth structure of the reduced cup rate Nd,CuO,,, : a combination of defect and excess oxygen non-stoichiometry phenomena, 895 Space group and lattice constants for barium cerate and minor corrections to the crystal structures of BaCe, ,Yo ,5 and BaCe0.9Gd0.102.95? 899 Magnetic structure of the 4,4,4',4',5,5,5',5'-0ctamethyl-2,7-m-phenylenebis(4,5-dihydroimidazol-l-oxyl3-oxide) biradical: quantum spin effect of S= 1 species associated with structural change, 9 15 Neutron diffraction study of the 'doubled perovskite' phases Ba,M, -,Cu,O, + (M =In, Sc), 92 1 Neutron powder diffraction study of (Bi, ,,Cu,,,,)YSr,Cu,O,, 93 1 Investigation into the structures of some normal alkane\ within the homologous series C13HZs to C,,H,,, using high-resolution synchrotron X-ray powder diffraction, 977 Phases in the Zr,Ta, -,(O,N)] system, formed by ammonolysis of Zr-Ta gels: Preparation of a baddeleyite-type solid solution phase ZrxTal-xOl+xN1-x, O<x<l, 1293 Synthesis and properties of a new P polymorph of Li,CrO,, 1307 YMoO, revisited: The crystal structure of Y,Mo,O,,, 1457 Powder neutron diffraction study of the Nasicon-related phases NaxM'1xM1'12-x(SO,), -,( SO4),: MI' = Mg, M"' = Fe, Iri, 1469 Crystal structure of U,Pt,Sn: A new derivative of the tecragonal U,Si,-type structure, 1893 Powder neutron diffraction Neutron diffraction structural study of the Nasicon-related phases Li,M1l,M1ll, -,(SO,), -,( SeO,), (MI'= Mg, Ni, Zn; M"' =Al, Cr), 1463 Precursor Synthesis of mullite fibre from an aluminosiloxane Precursor, 353 In situ study of a strontium P-diketonate precursor for thin-film growth by atomic layer epitaxy, 1239 Synthesis, crystal structure and properties of [SrzCu(C,O,),( H,O),]: Precursor of Sr,CuO, oxide, 1867 Pre-tilt angle Pre-tilt angles as a function of polyimide composition for copolyimides, 1667 Protonic conduction AC and DC electrochemical investigation of protonic c( mduction in calcium-doped barium cerate ceramics, 509 Crystal structure of the high-temperature protonic conductor SrCeO,, 867 Investigations of structure and protonic conductivity in the so-called tin zeolites, 19 13 Investigations of structure and protonic conductivity in composites of hydrous antimony(v) oxide and mordenite, 1921 Pyrolysis Mechanisms of pyrolysis of organometallic deposition precursors, 13 Racemization Devil's staircase and racemization in antiferroelectric liy uid crystals, 237 Radio-labelling Kinetic and simulation studies of linear epoxy systems, 385 Radio1 ysis a-GeC precursors obtained by radiolysis of GeH4-hydrocarbon mixtures, 1067 y-Radiation sol-gel synthesis of glass-metal nanocomposites, 1619 Raman spectroscopy FTIR and Raman spectroscopic investigation of 2,2'-bipyridine adsorption on silica, alumina, zirconia and titania, 557 Rare-earth-metal ions Instability of Y- and rare-earth-substituted Bi( Pb)-2223 phase, 1077 xv Red bismuth Red bismuth emission in alkaline-earth-metal sulfates, 1349 Refractive index Preparation and characterization of heavy-metal oxide glasses: Bi,O,-PbO-B,O3-GeO2 system, 529 Synthesis of high refractive index acrylic copolymers, 1359 Relaxer material Preparation of single-phase Pb( Mg1,3Nb2,3)03 samples utilizing information from solubility relationships in the Pb-Mg-Nb-citric acid-H,O system, 1271 Resin Comparison of porosity characteristics of macroporous poly(styrene-divinylbenzene) resins determined from mercury intrusion data and image analysis of transmission electron micrographs, 253 Preparation and characterization of imidazole-metal complexes and evaluation of cured epoxy networks, 379 Kinetic and simulation studies of linear epoxy systems, 385 Comparative kinetic analyses for epoxy resins cured with imidazole-metal complexes, 1793 Resist A new single-layer plasma-developable photoresist using the catalysed crosslinking of poly(4-hydroxystyrene) tlia photogenerated acid, 1533 Laser photolytic studies on sensitizers for negative photoresists: 4,4'-Diazido-3,3'-dimethoxybiphenylin poly(methy1 methacrylate) films, 1539 Rietveld refinement Polymorphism and crystal chemistry of Li,,,Ga,,,GeO,, an Li,PO, analogue, 457 Preparation, structure and magnetic properties of a new nickel(m) oxide: YbSr3NiO6, 575 Ruthenium oxide Composite materials based on Ti and Ru oxides, 373 Scanning electron microscopy Preparation of zinc oxide and zinc sulfide powders by controlled precipitation from aqueous solution, 161 1 Sebacic acid Reaction of molten sebacic acid with a layered (Mg/Al) double hydroxide, 99 Secondary ion mass spectrometry Characterization of Ru0,-based film electrodes by secondary ion mass spectrometry, 1255 Second-harmonic generation Second-harmonic generation from thick all-polymeric Langmuir- Blodgett films prepared using polyurethanes, 1 Synthesis and second-harmonic generation properties of 2-(4-nitroanilino)-l,3,5-triazinederivatives, 1571 Seebeck effect High-temperature thermoelectric properties of In,O,-based mixed oxides and their applicability to thermoelectric power generation, 653 Self-assembled monolayer Competing interactions in self-assembled monolayers containing peptide groups: molecular dynamics studies of long-chain perfluoro mercaptans on Au( 11 l),793 Self-propagating route Self-propagating routes to transition-metal phosphides, 279 Semiconductivity X-Ray absorption spectroscopic study of the binary semiconducting glass PbV,O,, 943 Selectivity and composition dependence of response of gas-sensitive resistors. Part l.-Propanexarbon monoxide selectivity of Ba,Fe,Nb,,-,O,, (16 x d2), 1427 Semiconductor Chemomechanical polishing of gallium arsenide and cadmium telluride to subnanometre surface finish.Evaluation of the action and effectiveness of hydrogen peroxide, sodium hypochlorite and dibromine as reagents, 29 Dopant and impurity effects in electrodeposited CdS/CdTe thin films for photovoltaic applications, 41 Alternative single-source precursor for growth of indium pnictide thin layers, 51 Electroluminescence of Ho3+ ions in semiconducting polycrystalline zinc oxide electrodes in contact with aqueous electrolyte, 139 xvi Nano/nanocomposite systems: In situ growth of particles and clusters of semiconductor metal sulfides in porous silica-pillared layered phosphates, 189 Studies of the spinel solid solution Co2Ru,-,FexO4, 515 H,S-sensitive thin film fabricated from hydrothernially synthesized SnO, sol, 631 Li,Ni,Ta06: A novel rock salt superstructure phase with partial cation order, 1303 Synthesis, crystal structure and properties of [Sr,Cu(C,O,),(H,O),]: Precursor of Sr,CuO, oxide, 1867 Sensor Amperometric PbSnF,-based oxygen sensors: rapid response at room temperature in the operating pressure range 10 kPa-7.2 MPa, 973 Improvement of copper oxide-tin oxide sensor for dilute hydrogen sulfide, 1259 SiAlON Solid-state NMR examination of the formation of 13-SiAlON by carbothermal reduction and nitridation of hallo ysite clay, 245 Influence of methane on the nitriding gas reduction of kaolinite, 669 Synthesis of p-Si AION from clays: Effect of starting materials, 1137 Side-chain liquid crystal Effect of spacer length on the thermal properties of side-chain liquid-crystal poly (methacrylate)s, 1705 Silica FTIR and Raman spectroscopic investigation of 2.2'-bipyridine adsorption on silica, alumina, zirconia and titania, 557 Photocontrolled aggregation of colloidal silica, 88 7 Influence of preparation methods on the texture and structure of titania supported on silica, 903 Preparation and characterisation of novel polypyrrole-silica colloidal nanocomposites, 935 Effect of preparation methods on properties of amorphous alumina/silicas, 1131 Synthesis, characterization, chemisorption and thermodynamic data of urea immobilized on silica, 1479 Silicated anatase Characterisation of silicated anatase powders, 1755 Si1icon Silicon-germanium films for photomasking applications, 393 Selective removal of silicon from zeolite frameworks using sodium carbonate, 605 Silicone fluid Gelation of silicone fluids using cholesteryl esters ;is gelators, 1181 Silicon nitride Role of additives in the sintering of silicon nitride: A 29Si, "Al, *'Mg and "Y MAS NMR and X-ray diffraction study, 1595 Bonded hydrogen in silicon nitride films deposited by remote plasma-enhanced chemical vapour deposition, 1843 Siloxane Synthesis and properties of low-molar-mass liquid-crystalline siloxane derivatives, 869 Relaxation behaviour of NLO chromophores grafted in hybrid sol-gel matrices, 1855 Silver y-Radiation sol-gel synthesis of glass-metal nanocomposites, 1619 Sintering Effects of sintering conditions on hydroxyapatite for use in medical applications: A powder diffraction study, 185 Role of additives in the sintering of silicon nitride: A "Si, "Al, ',Mg and 89Y MAS NMR and X-ray diffraction study, 1595 Smectic liquid crystal Antiferroelectric chiral smectic liquid crystals, 997 Smectite clay Studies of the sorption of triethyl phosphate by ion-exchanged smectite clays, 565 Sodium tungsten bronze Investigation of the oxidation of Na,WO, surfaces.1647 Sol-gel process Chemical lithium insertion into sol-gel lamellar manganese dioxide MnO,,,, -nH,O, 133 High-purity WO, sol-gel coatings: Synthesis and characterization, 407 Effect of preparation methods on properties of aluminaititanias, 585 Preparation of ZnO-based varistors by the sol-gel technique, 615 Photochromic behaviour in the fluorescence spectra of 1,2-bis(9-acetoxy-10-anthry1)ethanein silicate glass prepared by the sol-gel method, 635 Effect of drying temperature on the physical properties of titania aerogels, 65 1 Structural and electrochemical properties of layered manganese dioxides in relation to their synthesis: classical and sol-gel routes, 875 Sol-gel processing of niobium chloroalkoxides, 1093 Porosity of pyrolysed sol-gel waveguides, 1263 Preparation of single-phase Pb( Mg,,,Nb,,,)O, samples utilizing information from solubility relationships in the Pb-Mg-Nb-citric acid-H20 system, 127 1 Synthesis and characterization of Ni,Sb,(OEt),6 and its hydrolysis products, 1275 Phases in the Zr,Ta, -,(O,N),, system, formed by ammonolysis of Zr-Ta gels: Preparation of a baddeleyite-type solid solution phase Zr,Tal-,Ol+,N1-,, O<x< 1, 1293 Relaxation behaviour of NLO chromophores grafted in hybrid sol-gel matrices, 1855 Sol-gel synthesis Organic-inorganic hybrid solids.Control of solid formation by intermolecular interactions: evidence for a template effect, 987 Sol-gel synthesis of superconducting YBa,Cu,O, using acetate and tartrate precursors, 1267 -[-Radiation sol-gel synthesis of glass-metal nanocomposites, 1619 Solid electrolyte Ge-doped bismuth vanadate solid electrolytes: synthesis, phase diagram and electrical properties, 525 Preparation of an Na,Zr,Si,PO,,-sodium aluminosilicate composite and its application as a solid-state electrochemical CO, gas sensor, 663 Bi,W,_,Cu,O,-, (0.7dxd0.8): A new oxide-ion conductor, 703 Phase diagrams and stoichiometries of the solid electrolytes, Bi,V,Oll : M, M = Co, Cu, Zn, Ca, Sr, 1441 Structure of LiN(CF3S02)*, a novel salt for electrochemistry, 1579 Solid solution New Li+-ion conductors, Li4-,,Ti1 -,S,O, based on the Li,Ti04 structure, 1075 Superconductivity up to 95 K in mercury-substituted 1212 thallium cuprates (T1,Hg),Sr2+yNdl-yC~207+6,1353 Phase diagrams and stoichiometries of the solid electrolytes, Bi,V,OI1 : M, M=Co, Cu, Zn, Ca, Sr, 1441 Solid-state materials Computer modelling as a technique in materials chemistry, 781 Solid-state reaction Novel synthetic pathway to Bi( Pb)-2223 phase with variable Ca : Sr ratio, Bi,~,Pb0~,Sr,-,Ca,Cu30,: 1.85G x G2.4, 647 Solubility Preparation of single-phase Pb( Mg1,3Nb2,3)03 samples utilizing information from solubility relationships in the Pb-Mg-Nb-citric acid-H,O system, 1271 Spin coating Preparation of gold-dispersed vanadium oxide thin films by an alternate spin-coating method for electrochromic applications, 1581 Spinel Atomistic simulation of the surface structure of spinel, 813 Characterization of coprecipitated Fe,O,-AI,O, powders, 1123 Stabilised urania Electrode kinetic behaviour of (~0.4Pr0.6)0~~~/YSZ/(u0.~pr0.6~02fx 1437 Statistical analysis Statistical analysis of apatitic tricalcium phosphate preparation, 765 Structure-property relationship Structure-property relationships of some amorphous and crystalline aluminophosphates, 33 1 Sulfides New routes to alkali-metal-rare-earth-metal sulfides, 1603 Superconductivity Atomistic mechanisms of oxygen diffusion in YBa,Cu,O, -,and YBa,Cu,O,, 299 Influence of ionic substitution on the magnetic behaviour of Y,Cu,O.j, 417 Selection of appropriate systems for flux growth of single-crystal YBa2Cu30,-,, 469 Quaternary uranium copper oxides: The structure and properties Of UBa2CUO6, 475 Novel synthetic pathway to Bi( Pb)-2223 phase with variable Ca :Sr ratio, Bi,,,Pbo ,Sr,-,Ca,Cu30,: 1.85dx d2.4, 647 Structural and defect properties of high-T, oxides determined by atomistic lattice simulation, 817 Neutron diffraction study of the ‘doubled perovskite’ phases Ba,M, -,Cux04+ (M =In, Sc), 921 Neutron powder diffraction study of ( Bio,35Cuo,65)YSrz(:uZO7, 93 1 Synthesis and superconducting properties of HgBa,Ca,~~u,O, + x, 99 1 Instability of Y-and rare-earth-substituted Bi( Pb)-2223 phase, 1077 X-Ray absorption studies of Bi-based superconductors, 108 1 Sol-gel synthesis of superconducting YBa,Cu,O, using acetate and tartrate precursors, 1267 Superconductivity up to 95 K in mercury-substituted 1212 thallium cuprates (T1,Hg),Sr,+,Ndl.,Cu,O, 1353 YBCO and BSCCO thin films prepared by wet MOCV D, 1585 Thallium solubility range in Tl,_,Ba,Ca,- 1C~,0Zn+4-x superconductors, 1627 Chemical routes for preparation of oxide high-temperature superconducting powders and precursors for superconductive ceramics, coatings and composites, 1659 Formation and decomposition of LaBa,Cu30, +, 1745 Superstructure Li,Ni,TaO,: A novel rock salt superstructure phase with partial cation order, 1303 Supported catalyst Novel preparation of highly dispersed tungsten oxide on silica, 1343 Surface texture Influence of preparation methods on the texture and structure of titania supported on silica, 903 Synchrotron radiation Investigation into the structures of some normal alkanes within the homologous series C,,H,, to C6oH1,, using high-resolution synchrotron X-ray powder diffraction, 977 Tellurite glass Local range order of tellurium atoms in Te0,-BaO and Te02-BaF, glassy systems, 1101 Influence of chlorine-oxygen substitution on the electrical properties of some oxychloride tellurite glasses, 1433 Template Organic-inorganic hybrid solids.Control of solid forma tion by intermolecular interactions: evidence for a template etrect, 987 Ternary oxide Self-consistent interatomic potentials for the simulation of binary and ternary oxides, 831 Phase diagram of the Bi-Sr-Cu-0 system, 1871 Ternary stannide Crystal structure of U,Pt,Sn: A new derivative of the tetragonal U,Si,-type structure, 1893 Ternary sulfide New Routes to Alkali-metal-rare-earth-metal sulfides, 1603 Tetragonal tungsten bronze Selectivity and composition dependence of response of gas- sensitive resistors.Part 1. -Propaneecarbon monoxide selectivity of Ba6Fe,Nblo-,030 (1dx d2), 1427 Tetrathiafulvalene Crystal structures and electrical properties of the radical salts of the unsymmetrical donor EOTT (4,5-ethylenedithio-4’,5’-(2-oxatrimethylenedithio) tetrathiafulvalene), 1559 X-Ray crystal structure and solid-state properties of a I :1 complex of tetrathiafulvalene (TTF) and l-oxo-2,6-dimethyl-4- dicyanomethylenecyclohexa-2,5-diene, 1719 Thallium Thallium solubility range in TI, -,Ba2Can-,Cu,02, + ,-superconductors, 1627 Thermal analysis Effect of composition on the lattice parameters and thermal behaviour of nickel(rr)-cobalt(II) hydroxide nitrate solid solutions, 61 1 Mesomorphic arylethynes and their precursors, 1017 Thermal behaviour and reactivity of manganese cobalti tes Mn,Co, -,04(0.0<x < 1.0) obtained at low temperature, 1635 xvii Thermal decomposition Free radical generation during thermal decomposition of azoisobutyronitrile in nematic liquid crystal mixtures, 761 Catalytic activity of aluminas obtained by the thermal decomposition of mechanically ground alumina monohydrates, 3-and P-Al,O,.H,O, 1503 Thermal deposition Single-crystal study of topotactic changes between NH,VO, and V,O,, 1475 Thermally stimulated depolarisation current technique Electret behaviour of di- and tri-nuclear iron hydrazone- hexacyanoferrate compounds studied by the thermally stimulated depolarization current technique, 713 Thermodynamics Calculated enthalpies of mixing of MnO/MgO and NiO/MgO, 825 Thermoelectricity High-temperature thermoelectric properties of In,O,-based mixed oxides and their applicability to thermoelectric power generation, 653 Thermogravimetr y Behaviour of ceria under hydrogen treatment: Thermogravimetry and in situ X-ray diffraction study, 1927 1,3,CThiadiazole Bulk properties and monolayer behaviour of diol-based mesogens and their acetonides, 1021 Thin film Alternative single-source precursor for growth of indium pnictide thin layers, 51 Organo-soluble segmented rigid-rod polyimide films.Part 5.-Effect of orientation, 105 Silicon-germanium films for photomasking applications, 393 High-purity W03 Sol-gel coatings: Synthesis and characterization, 407 Oriented microporous film of tetramethylammonium pillared saponite, 519 H,S-sensitive thin film fabricated from hydrothermally synthesized SnO, sol, 631 Electroluminescence of organic thin films based on blends of polystyrene and fluorescent dyes, 675 Co-pyrolysis of hydrocarbons and SiEt, for the synthesis of graduated Si,C1 ~x ceramic thin films by chemical vapour deposition, 695 Synthesis, characterization and crystal structure of a new thermally stable and volatile precursor [bis( 1,1,1,2,2,3,3,7,7,8,8,9,9,9-tetradecafluorononane-4,6-dionato),-tetraglyme] barium(11) for MOCVD application, 1061 Electrochromic tungsten oxide: Doping with two or three other metal oxides, 1071 Sol-gel processing of niobium chloroalkoxides, 1093 Surface oxidation of poly ether ether ketone using ultraviolet/ozone, 11 57 Monolayer behaviour and Langmuir-Blodgett film properties of some amphiphilic phthalocyanines: Factors influencing molecular organisation within the film assembly, 1205 In situ study of a strontium P-diketonate precursor for thin-film growth by atomic layer epitaxy, 1239 Investigations into the growth of A1N by MOCVD using trimethylsilylazide as nitrogen source, 1245 Growth of ZnO by MOCVD using alkylzinc alkoxides as single-source precursors, 1249 MOCVD of high-quality YBa,Cu,O, -6 films: in situ preparation of fluorine-free layers from a fluorinated barium source, 1393 Growth of TiO, overlayers by chemical vapour deposition on a single-crystal copper substrate, 1403 Growth of PbS thin films from novel precursors by atomic layer epitaxy, 1409 Preparation of gold-dispersed vanadium oxide thin films by an alternate spin-coating method for electrochromic applications, 1581 YBCO and BSCCO thin films prepared by wet MOCVD, 1585 Time-resolved fluorescence spectroscopy Optical behaviour of sodium P-aluminogallate single crystals doped with Cr3+ and Cr3+-Nd3+, 907 Tin oxide sol H,S-sensitive thin film fabricated from hydrothermally synthesized SnO, sol, 631 Tin zeolite Investigations of structure and protonic conductivity in the so-called tin zeolites, 1913 Titania Composite materials based on Ti and Ru oxides, 373 FTIR and Raman spectroscopic investigation of 2,?’-bipyridine adsorption on silica, alumina, zirconia and titania, 557 Effect of preparation methods on properties of aluniina/titanias, 585 Effect of drying temperature on the physical properties of titania aerogels, 651 Influence of preparation methods on the texture arid structure of titania supported on silica, 903 Solid-state and surface chemistry of CuO-TiO, (artatase) powders, 965 Plasma-enhanced chemical vapour deposition of TlOJpolymer composite layers, 1055 Characterisation of silicated anatase powders, 1755 Titanium nitride Vapour-phase synthesis of titanium nitride powder. 689 Titanium tetraisopropoxide Growth of TiO, overlayers by chemical vapour deposition on a single-crystal copper substrate, 1403 Topotactic exchange Ion exchange of ruthenium cationic complexes by x-tin@) bismonohydrogenphosphate, 1337 Single-crystal study of topotactic changes between NH,VO, and V2OS,1475 Transition-metal complex Discotic liquid crystals of transition-metal complexes, 537 Transition-metal hydroxide Electrogeneration of base by cathodic reduction of anions: novel one-step route to unary and layered double hydroxides (LDHs), 1487 Transition-metal phosphide Self-propagating routes to transition-metal phosphides, 279 Transmission electron microscopy Comparison of porosity characteristics of macroporous poly (styrene-divinylbenzene) resins determined from mercury intrusion data and image analysis of transmission electron micrographs, 253 Magnetic measurements and transmission electron microscopy investigations on Fe-Co ultrafine powders derived from a bimetallic carbonyl cluster, 361 Triazine Synthesis and second-harmonic generation properties of 2-(4-nitroanilino)-1,3,5-triazinederivatives, 1571 Trimeth ylamine Assessment of a chromogenic calix [41arene for the rapid colorimetric detection of trimethylamine, 21 7 Tungsten oxide High-purity WO, Sol-gel coatings: Synthesis and characterization, 407 Determination of the potential limits for WO, colouration, 1289 Novel preparation of highly dispersed tungsten oxide on silica, 1343 Urea Dynamic properties of the urea molecules in x,w dibromoalkane/urea inclusion compounds investigated by ,H NMR spectroscopy, 35 Synthesis, characterization, chemisorption and thermodynamic data of urea immobilized on silica, 1479 Valency X-Ray absorption studies of Bi-based superconductors, 1081 Vanadium oxide Preparation of gold-dispersed vanadium oxide thin films by an alternate spin-coating method for electrochromic applications, 1581 Vanadium pentaoxide ”0 Nuclear magnetic resonance spectroscopy of the structural evolution of vanadium pentaoxide gels, 1749 Vanadium phosphate Vanadium phosphate glasses.Effect of composition on their structure and performance as cathodes in high-temperature lithium polymer-electrolyte cells, 11 3 Vapour-phase synthesis Vapour-phase synthesis of titanium nitride powder, 689 Vapour pressure Solid-state reaction between molybdena and alumina: Effect of water vapour pressure on the dispersion and nature of the supported phases, 47 xviii Varistor Preparation of ZnO-based varistors by the sol-gel technique, 615 Vermiculite Synthesis of QMD and QD polyorganosiloxanes from tetrakis( trimethylsi1oxy)silane and palabora vermiculite, 399 Waveguide Porosity of pyrolysed sol-gel waveguides, 1263 Wide-angle X-ray diffraction Organo-soluble segmented rigid-rod polyimide films.Part 5. Effect of orientation, 105 XANES Local range order of tellurium atoms in Te0,-BaO and Te0,-BaF, glassy systems, 1101 XPS Physical properties of polypyrrole films containing dicyanoaurate(1) anions, PPy-Au(CN),, 87 Role of Ol-, OH- and anion vacancies in the degradation of Y-TZP in moist environments, 257 XPS investigations of acid-base interactions in adhesion. Part 4.--Use of trichloromethane as a molecular probe for the quantitative assessment of polymer basicity, 305 High-purity WO, sol-gel coatings: Synthesis and characterization, 407 Surface studies of polyethylene modified by flame treatment, 487 Intercalation of organic compounds in the layered host lattice MOO,, 551 Studies of vapour-phase chemical derivatisation for XPS analysis using model polymers, 683 Surface oxidation of poly ether ether ketone using ultraviolet,'ozone, 1157 Bulk and surface characterization of some heteropolymolybdates and the products of their reduction and sulfidation, 1641 X-Ray absorption spectroscopy X-Ray absorption spectroscopic study of the binary semiconducting glass PbV,O,, 943 X-Ray absorption studies of Bi-based superconductors, 1081 X-Ray absorption spectroscopic study of the A1P04-5: ferrocene inclusion compound and its thermally decomposed products, 1723 X-Ray diffraction Ab irtitio determination of crystal structures by X-ray powder diffraction: Structure of Li,,Zr,Nb,O,,, 167 Pillared hydroxycarbonates and mixed oxides.Part 1.-Copper-zinc cobalt-aluminium system, 197 Role of 02-,OH- and anion vacancies in the degradation of Y-TZP in moist environments, 257 Studies of model macroscopic-defect-free materials. Part 1.- Investigations of the system 4Ca0 -Al,O, -Fe,03-4Ca0 -3A1,O3 SO,-hpmc-H,O by X-ray thermoanalytical and NMR techniques, 265 Studies of model macroscopic-defect-free materials. Part 2.-Microstructure and open porosity in the system 4Ca0 .A1,0, -Fe203 -4Ca0- 3AI20, -SO,-hpmc-H,O, 271 Synthesis and crystal structure of Li,NaTa,O,,, 445 Polymorphism and crystal chemistry of Li,,,Ga,,,GeO,, an Li,PO, analogue, 457 Crystal structure of the ternary silicide U,RuSi,: A new ordered version of the hexagonal AlB,-type structure, 463 Quaternary uranium copper oxides: The structure and properties of UBa,CuO,, 475 Cation ordering in distorted perovskites (MLa)( MgTe)O,, M =Na.K, 547 Intercalation of organic compounds in the layered host lattice MOO,, 551 X-Ray analysis of two phases in the barium borate, sodium barium borate and sodium borate ternary phase diagram, 571 Preparation, structure and magnetic properties of a new nickel(Ir1) oxide: YbSr,NiO,, 575 Selective removal of silicon from zeolite frameworks using sodium carbonate, 605 Effect of composition on the lattice parameters and thermal behaviour of nickel(r1)-cobalt (11) hydroxide nitrate solid solutions, 61 1 Study of the Ru-Mo-0 and Ru-W-0 phase systems; rutile solid solutions Ru,-,MXO2, 641 Crystal structures of two sodium yttrium molybdates: NaY and Na,Y (MOO,),, 707 (BaTiO,),(Ge,Ce),Cu,O,: A new homologous series of layered cuprates containing various layers of perovskite units, 773 Novel use of molecular dynamics simulation in studying structure-property relationships in the solid infrared laser medium Na+-Er3+ P"-alumina, 839 Crystal structure of the high-temperature protonic conductor SrCeO,, 867 Structure of BiBr,Ph: a solid-state architecture involving secondary bonding and n-n interactions, 89 1 Perovskite-like intergrowth structure of the reduced cuprate Nd,CuO, 5: a combination of defect and excess oxygen non-stoichiometry phenomena, 895 Magnetic structure of the 4,4,4',4',5,5,5',5'-octamethyl-2.2'-nt- phenylenebis (4,5-dihydroimidazol- 1-oxyl 3-oxide) birddical: quantum spin effect of S= 1 species associated with structural change, 915 Solid-state and surface chemistry of CuO-TiO, (anatase) powders, 965 Investigation into the structures of some normal alkanes within the homologous series C,3H2s to C,,H,,, using high.resolution synchrotron X-ray powder diffraction, 977 Superconductivity up to 95 K in mercury-substituted 1912 thallium cuprates (T1,Hg),Sr,+,Ndl-,Cu207 +6.1353 MOCVD of high-quality YBa,Cu,O,-, films: in situ preparation of fluorine-free layers from a fluorinated barium source, 1393 Role of additives in the sintering of silicon nitride: A 29Si, 27Al, "Mg and 89Y MAS NMR and X-ray diffraction study, 1595 Bulk and surface characterization of some heteropolymolybdates and the products of their reduction and sulfidation, 1641 Formation and decomposition of LaBa,Cu,O, -&, 1745 Phase diagram of the Bi-Sr-Cu-0 system, 1871 Behaviour of ceria under hydrogen treatment: Thermopravimetry and in situ X-ray diffraction study, 1927 Yttria Role of O2-,OH- and anion vacancies in the degradation of Y-TZP in moist environments, 257 Yttrium molybdenum oxide YMoO, revisited: The crystal structure of Y,Mo,O,,, 1457 Zeolite Selective removal of silicon from zeolite frameworks using sodium carbonate, 605 New route for dispersion of inorganic salts onto the chmnel surfaces of microporous crystals: high dispersion of ( uC1, in zeolites using a microwave technique, 735 Pillared layered structures rs.zeolites as sorbents and catalysts. Part 1.-Hydrocarbon separations on two alumina-pillared clays and an r-tin phosphate analogue, 959 Modified zeolites for the removal of calcium and magnesium from hard water, 1143 Cyclic voltammetry of zeolite-supported manganese pot phyrins, 1215 Investigations of structure and protonic conductivity in the so-called tin zeolites, 1913 Investigations of structure and protonic conductivity in composites of hydrous antimony(v) oxide and mordenite, 1921 Zinc dimethyl phosphate Zinc dimethyl phosphate, Zn [O,P(OCH,),], ,a one-di mensional inorganic polymer, 11 1 1 Zinc oxide Electroluminescence of Ho3+ ions in semiconducting polycrystalline zinc oxide electrodes in contact with ;Iqueous electrolyte, 139 Preparation of zinc oxide and zinc sulfide powders by tkontrolled precipitation from aqueous solution, 161 1 Zinc sulfide Preparation of zinc oxide and zinc sulfide powders by controlled precipitation from aqueous solution, 161 1 Zirconia Role of 02-,OH-and anion vacancies in the degradation of Y-TZP in moist environments, 257 FTIR and Raman spectroscopic investigation of 2,2'-bipyridine adsorption on silica, alumina, zirconia and titania, 557 Zirconia formation by reaction of zirconium sulfate in molten alkali-metal nitrates or nitrites, 1331 xix Role of oxoanions in the stabilization of tetragonal zirconia, 1653 Zirconium phosphate Chemical vapour deposition of ZrO, thin films monitored by IR Mixed alumina-chromia pillared layered a-zirconium phosphate, spectroscopy, 1815 179 Zirconium oxochloride Examination of the orientation dependence of the quasielastic Preparation and characterization of encapsulated solid particles, scattering of neutrons by pellicular zirconium phosphate film, composed of partially hydrolysed aluminium and zirconium 1313 oxochlorides.337 xx Conference Diary 1994 December 8-9 European Workshop on Chemical Sensors for Metallurgical Processes Mol, Belgium F. De Schutter, Energy Division, VITO, Boeretang 200, B-2400 Mol, Belgium. Fax: +32 14 32 1185. December 15-16 C-MRS and E-MRS Joint Symposium on Electronic and Optoelectronic Materials Beijing, China Professor Yang Xiongfeng, Secretary General of the Symposium, Institute of Semiconductors, Chinese Academy of Sciences, P.O.Box 912, Beijing 100083, China. Tel: +86 01 255 8131 ext. 321; Fax: +86 1256 2389. December 19-22 1994 International Conference on Electronic Materials (ICEM'94) Bt 1994 IUMRS International Conference in Asia (IUMRS-ICA) Hsinchu, Taiwan C/o Materials Research Laboratories, ITRI, Conference Department, IUMRS-ICEMACA'94, Bldg 77,195 Chung-hsing Rd, Sec. 4, Chutung, Hsinchu, 3105, Taiwan, ROC. Tel: +886 35 820064/916801; Fax: +886 35 820247/820262. 1995 January 5-6 Plastics for Portable Electronics Las Vegas, NV, USA Dr.hoop Agrawal, Donnelly Corporation, 4545 E. Fort Lowell Road, Tucson, AZ 85712, USA. Tel: +1602 321 7680; Fax +1602 322 5635. January 29- Advanced Solid-state Lasers February 1 Memphis, TN, USA Optical Society of America, 2010 Massachusetts Avenue, NW, Washington, DC 20036, USA. Tel: +1202 223 8130; Fax: +1202 416 6130. February 16 Radiation Curing and Processing of Materials London, UK SCI Conference Secretariat, 14/15 Belgrave Square, London, UK, SWlX 8PS. Tel: +44 171 235 3681; Fax: +44 171 823 1698. 0 February 16-17 VIIIth Colloquium on Biomaterials Aachen, Germany Dr. H.A. Richter, Institute of Pathology, Technical University Aachen, Pauwelsstraoe 30, 52074 Aachen, Gemany. Tel: +49 241 80 89690; Fax: +49 241 8888 439.March 4-11 IWEPNM 95: International Winterschool on Electronic Properties of Novel Materials, Fullerides and Fulleroides Kirchberg, Tyrol, Austria Professor H. Kuzmany, Inst. f. Festkorperphysik der Universitat Wien, Strudlhofg. 4, A-1090 Vieana, Austria. March 5-10 ECLC 95: European Conference on Liquid Crystals Bovec, Slovenia Dr. Igor MuSeviE, ECLC 95, J. Stefan Institute, Jamova 39, P.O.B. 100, 61111 Ljubljana, Slovenia, E-mail: igor.musevic@ijs.si; Fax: +386 61 219385/273677. 0 March 12-15 Second European East West Workshop on Chemistry and Energy Sintra, Portugal CBsar Sequeira, Instituto Superior Tkcnico, Av. Rovisco Pais, 1096 Lisboa Codex, Portugal. TeVFax: +351 1 778 3594. March 13-15 Low- and No-VOC Coating Technologies: 2nd Biennial International Conference Durham, NC, USA Ms.Coleen M. Northeim, Research Triangle Institute, P.O. Box 12194,Research Triangle Park, NC 27709-2194,USA. Tel: +1 919 541 5816; Fax: +1 919 541 7155. 0 March 19-22 FAMCC 1995 Florida Advanced Materials Chemistry Conference Palm Coast, FL, USA Daniel R. Talham, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA. Tel: +1904 392 9016; Fax: +1904 392 3255. 0 March 29-31 British Liquid Crystal Society, Annual Conference Exeter, UK Professor Roy Sambles, Department of Physics, University of Exeter, Exeter, UK, EX4 4QL. April 2-6 Seventh Biennial Workshop on Organometallic Vapor Phase Epitaxy Fort Meyers, FL, USA TMS Meeting Services Department, 420 Commonwealth Drive, Warrendale, PA 15086, USA.E-mail: wilson@tms.org; Tel: +1412 776 9000 ext. 241; Fax: +1412 776 3770. April 3-6 ECIO '95: 7th European Conference on Integrated Optics Delft, The Netherlands ECI0'95 Secretariat, P.O. Box 5031, 2600 GA Delft, The Netherlands. Tel: +31 15 78 1034; Fax: +31 15 78 4046. April 24-26 19th International Power Sources Symposium 1995 Brighton, Sussex, UK T. Keily (Chairman), International Power Sources Symposium Committee, 1Oakley Drive, Fleet, Hampshire, UK, GU13 9PP. April 24-28 ICMCTF 1995: International Conference on Metallurgical Coatings and Thin Films San Diego, CA, USA Mary S. Gray, ICMCTF 95, Suite 502, 1090 G Smallwood Drive, Waldorf, MD 20603, USA.Tel: +1 301 870 8756; Fax: +1301 645 1426. May 7-10 13th International Conference of Fluidized Bed Combustion Kissimmee, FL, USA Leslie Friedman, Meetings Manager, The American Society of Mechanical Engineers, 345 East 47'h Street, New York, NY 10017-2392, USA. Tel: +1 212 705 7788; Fax: +1 212 705 7856. May 9-13 7th International Conference on Indium Phosphide and Related Materials Sapporo, Hokkaido, Japan IEEELEOS, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-1331, USA. Tel: +1908 562 3893; Fax: +1 908 562 8434. May 21-26 CL,EO/QELS: Conference on Lasers and Electro-optics & Quantum Electronics and Laser Science Conference Baltimore, MD, USA IEEEYLEOS, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-1331, USA.Tel: +1 908 562 3893; Fax: +1908 562 8434. May 28- 2nd Mediterranean Workshop and Technical Meeting-Novel Optical Materials and Applications June 2 Cetraro, Italy Prof. I.C. Khoo, Electrical Engineering Department, Pennsylvania State University, University Park, PA 16802, USA. Tel: +1814 863 2299; Fax: +1814 865 7065. 0 May29- COLA '95: The Third International Conference on Laser Ablation June 2 Strasbourg, France E. Fogarassy, CNRS, Laboratoire Phase, BP 20, 67037 Strasbourg Cedex 2, France. Tel: +33 88 10 62 57; Fax: +33 88 10 62 93. 0 June6-9 4th International Symposium on Metallomesogens Cetraro, Italy Dr. Francesco Neve, Dipartimento di Chimica, Universita della Calabria, 87030 Arcavacata di Rende, (CS), Italy.Fax: +39 984 492044. June 21-23 International Liquid Crystal Workshop on Surface Phenomena St. Petersburg, Russia Research Centre, Vavilov State Optical Institute, Birzhevaya Line 12, 199034, St. Petersburg, Russia. Fax: +7 812 218 13 35. June 26-30 10th International Conference on Integrated Optics and Optical Fiber Communication Hong Kong BDG Communications Mgmt Ltd., IOOC'95 Conference Secretariat, Suite 1104-5, East Town Building, 41 Lockhart Road, Hong Kong. Tel: +852 528 6136; Fax: +852 865 1528. July 17-20 MC2: 2nd International Conference on Materials Chemistry Canterbury, Kent, UK Dr. J. D. Wright, Chemical Laboratory, University of Kent, Canterbury, Kent, UK, CT2 7NH. July 24-27 FLC '95: 5th International Conference on Ferroelectric Liquid Crystals Cambridge, UK Prof.W.A. Crossland, Northern Telecom Research Professor of Photophysics, Department of Engineering, University of Cambridge, Cambridge, UK. Fax: +44 1223 330662. August 7-11 EPBDS XI: Eleventh International Conference on the Electronic Properties of Two-Dimensional Systems Nottingham, UK Prof. L. Eaves (EP2DS XI Chairman), Department of Physics, University of Nottingham, Nottingham, UK, NG7 2RD. E-mail: ppzpcm@ppnl.nott.ac.uk; Fax: +44 115 9 515180. August 19-25 Clays and Clay Materials Science: Euroclay '95 Leuven, Belgium Professor P. Grobet, Secretary Euroclay '95, Centrum voor Oppervlaktechemie en Katalyse, KU Leuven, K Mercierlaan 92, B-3001 Heverlee, Belgium.Tel: +32 16 220931; Fax +32 16 295126. August 27- ISCOM'95: International Symposium on Crystalline Organic Metals, Superconductors and Ferromagnets September 1 Mittelberg, Kleinwalsertal, Austria ISCOM'95, Prof. Heimo J.Keller, Anorganisch Chemisches Institut, Universitat Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany. Tel: +49 6221 562 438; Fax: +49 6221 564 197. September 11-14 Euro-Fillers95: International Conference on Fillers in Polymers Mulhouse, France Dr. E. Papirer, CRPCSS-CNRS, 24 av. Pdt. Kennedy, F-68200 Mulhouse, France. Tel: +33 89 42 01 55; Fax: +33 89 32 09 96. September 11-15 Electrochem'95 Bangor, Wales Dr. Maher Kalaji, Department of Chemistry, University of Wales, Bangor, Gwynedd, Wales, UK, LL57 2UW.Tel: +44 1248 351151 ext. 2516; Fax: +44 1248 370528. xxii September 11-16 LB7:The Seventh International Conference on Organized Molecular Films Numana, Ancona, Italy Dr. M. G. Ponzi Bossi, Scientific Secretary LB7, Istituto di Scienze Fisiche, Facolta' di Medicina e Chirurgia, via Ranieri 65, 60131 Ancona, Italy. E-mail: fismed@anfisi.cineca.it; Tel: +39 71 220 4606; Fax: +39 71 220 4605. September 13-15 EuroOMet '95 incorporating the 29th Metallographie-Tagung Friedrichshafen, Germany Deutsche Gesellschaft fur Materialkunde e.v., Adenauerallee 21, D-61440 Oberursel, Germany. Tel: +49 6171 4081; Fax: +49 6171 52554. September 17-21 2-ICPEPA: 2nd International Conference on Photo-Excited Processes and Their Applications Jerusalem, Israel Organizing Committee: ICPEPA-2, Professor A. Peled, Chairman, CTEH aff. Tau, 52 Golomb St., Holon 58102, Israel. E-mail: photoexe@ilctehol.bitnet; Tel: +972 3 502 8902; Fax: +972 3 502 8967. September 25-29 Workshop on Non-Equilibrium Phenomena in Supercooled Fluids, Glasses and Amorphous Materials Pisa, Italy Dr. Dino Leporini, Dipartimento di Fisica, Universita di Pisa, Piazza Torricelli, 2 1-56100 Pisa, Italy. E-mail: leporini@pifidpt.difi.unipi.it; Tel: +39 50 911284; Fax: +39 50 48277. September 25-29 OLC '96: VIth International Topical Meeting on Optics of Liquid Crystals Le Touquet, France Prof. M. Warenghem, OLC '95, C.R.U.A.L., FacultC Jean Perrin, Rue J. Souvraz, S.P. 18, F 62307 Lens Cedex, France. E-mail: warenghem@lip5nx.decnet.citilille.fr; Tel: +33 20 43 48 12; Fax: +33 20 43 40 84. October 9-12 27th International SAMPE Technical Conference Albuquerque, NM, USA Dr. Charles L. Hamermesh, SAMPE Technical Director, 1161 Parkview Drive, Covina, CA 91724, USA. Tel: +1 818 331 0616 ext. 602; Fax: +1818 332 8929. October 16-18 Asia Display '95 Hamamatsu, Japan Asia Display '95 Secretariat, do The Convention, Annecy Aoyama, 2F 2-6-12, Minami-Aoyama, Minato-ku, Tokyo 107, Japan. October 18-20 MOC '95: 5th Microoptics Conference Hiroshima, Japan K. Iga, Representative of the Microoptics Group, Optical Society of Japan (JSAP), Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama, Japan 227. Tel: +8145 922 1111ext.2064; Fax: +8145 921 0898. December 3-8 10th International Conference on Solid State Ionics Singapore B. V. R. Chowdari, Department of Physics, National University of Singapore, Singapore-0511. E-mail: phychowd@leonis.nus.sg; Tel: +65 772 2956; Fax: +65 777 6126. 1996 June 24-28 ILCC: 16th International Liquid Crystal Conference Kent, OH, USA 16th International Liquid Crystal Conference, Liquid Crystal Institute, Kent State University, P.O. Box 5190, Kent, OH 44242-0001, USA. E-mail: ILCC16@alice.kent.edu; Tel: +1 216 672 2654; Fax: +1 216 672 2796. August 4-9 IUPAC MACRO SEOUL '96: 36th IUPAC International Symposium on Macromolecules Seoul, Korea Dr. Kwang Ung Kim, Secretariat of IUPAC MACRO SEOUL '96, Division of Polymers, Korea Institute of Science and Technology,P.O. Box 131, Cheongryang, Seoul 130-650, Korea. E-mail: iupac@kistmail.kist.re.kr;Tel: +82 2 957 6104; Fax: +82 2 957 6105. a Denotes a new or amended entry this month ~ Entries in the Conference Diary are published free of charge. If you wish to include an announcement please send full details to: Journal of Materials Chemistry Editorial Office, Thomas Graham House, Science Park, Milton Road, Cambridge, UK, CB4 4WF Tel: +44 1223 420066; Fax: +44 1223 426017 xxiii

ISSN:0959-9428    

DOI:10.1039/JM99404BP111

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

J. MATER. CHEM., 1994, 4( 12), 1769-1773 Photoresists based on a Novel Photorearrangement of o-Nitrobenzyl ic Polymers A. Ajayaghosh,*ta M.V. George* and Tsuguo Yamaokab a Photochemistry Research Unit, Regional Research Laboratory (CSIR), Trivandrum 695 079, India Department of Image Science, Faculty of Engineering, Yayoi-Cho, 7-33, Inage-ku, 263 Japan A new photosensitive dicarboxylic acid, isophthalimido bis(a-methylamino-2-nitro-4-toluic acid) (4) was synthesized and characterized. Copolymerization of the corresponding acid chloride with diamines gave polyamides having photo- sensitive o-nitrobenzylic chromophores at symmetrical positions of every repeating unit. Photolysis of the new poly- amides resulted an interesting photorearrangement leading to the formation of azo polymers with carboxylic acid groups at the ortho positions. The polarity difference induced by the photorearrangement brings about a solubility difference between the irradiated and unirradiated polymers, which renders them useful as positive photoresist materials.Ciamician and Silberl as early as 1901 had observed that o-nitrobenzaldehyde underwent an interesting phototransform- ation leading to o-nitrozobenzoic acid. Since then, the photo- transformations of several o-nitrobenzylic systems have been examined by several groups of workers. Amit and Patchornick2 used the photochemistry of o-nitrobenzylic and related systems for temporary protection of functional groups, work which was extended later to many areas such as polymer- supported peptide synthesis and nucleotide synthesis.2p7 The same photorearrangement can induce large changes in the solubility of polymers and has led to the design of several deep-UV photoresists for microelectronic application^.',^ For example, Burzynski and Saenger" have used the Patchornick reaction to bring about solubility differences in poly(acry1ic acid) by photochemically deprotecting o-nitrobenzylic groups from their side-chain carboxylic esters.Another imaging system based on the photochemistry of o-nitrobenzyl esters of cholic acid was reported by Reichmanis et d." in which the solubility difference is achieved by a difference in dissolu- tion inhibition properties of o-nitrobenzyl cholic ester before and after exposure.The photochemistry of o-nitrobenzylic chromophores has also been used to design photodegradable polymer^.'^-'^ The backbone fragmentation in such polymers results in the reduction of the molecular weight of the polymer which eventually causes a change in solubility, sufficient for it to be useful as deep-UV positive photoresists. Several authors have also employed the photorearrangement of o-nitrobenzylic systems to generate p-toluene sulfonic and related acids from their esters, which catalyse the deprotection of poly(tert- butoxycarbonyl styrene^).'^.'^ Taking advantage of the photo- chemistry of o-nitrobenzylic systems, we previously designed a new photodegradable polyamide and a model compound which were subjected to detailed photochemical studies includ- ing nanosecond and picosecond laser flash photolysis experi- ments.18 Recently, we have reported the synthesis and phototransformations of polymers containing the o-nitro-benzylic chromophore in the main chain." The present paper describes the novel approach of inducing a solubility difference between the irradiated and unirradiated polymers through a polymer backbone rearrangement rather than the usual poly- mer chain degradation in designing positive resists and takes advantage of the phototransformation of the o-nitrobenzylic chromophore.t INSA-JSPS Exchange Fellow at the Department of Image Science, Chiba University August-December, 1993. $Also at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 01 2, India.Experimental Materials and Methods All solvents used in this study were dried and freshly distilled before use. p-Toluic acid and isophthaloyl dichloride were obtained from Aldrich and used without further purification. 4-a-Methylamino-3-nitro-p-toluic acid was prepared by the reported procedure." All melting points were determined on a Buchi 530 melting point apparatus and are uncorrected. IR spectra were recorded on a Perkin-Elmer 880 IR spectrometer. The electronic spectra were recorded using a Shimadzu 2100 spectrophotometer. 'H and 13C NMR spectra were recorded on a JEOL GSC-400 spectrometer, using TMS as internal standard. Mass spectra were recorded on a Finnigan MAT model 8430 or a JEOL JMS-HX505 HA mass spectrometer.Elemental analyses were carried out by the Midwest Microlab (Indianapolis, USA). Viscosity measurements were carried out at 32 "C using an Ubbelohde viscometer. All solution-phase photoreactions were carried out in Pyrex vessels using a Srinivasan-Griffin-Rayonet photochemical reactor (RPR) equipped with a 300 nm light source. Synthesis of Isophthalimido Bis(a-methylamino-2-nitro-4-toluic Acid) (3) To a solution of 4-r-methylamino-3-nitro-p-toluic acid (1) (4.2g, 20mmol) in aqueous sodium hydroxide (2 mol l-', 10 ml) was added isophthaloyl dichloride (2.30 g, 10 mmol) in chloroform (10 ml), drop wise with stirring. The reaction mixture was kept alkaline by the slow addition of aqueous NaOH (1 mol 1-l). After 2 h, chloroform was removed under reduced pressure and the remaining mixture was poured over crushed ice, followed by acidification with hydrochloric acid (1 mol 1-l).The precipitated solid was filtered, washed with water and dried under vacuum to give 5.2g (95%) of the dicarboxylic acid 3, mp 23 1-232 "C, after recrystallization from methanol. IR vmaX (KBr)/cm-l: 3200-2800 (broad, C02H), 1724 (C=O, acid), 1622 (C=O, amide), 1540 and 1355 (NO,). 'H NMR (C2H6]acetone) 6: 3.1 (s, 6 H, NCH3), 5.1 (s, 4 H, CH,), 7.5-8.7 (m, 10 H, aromatic). MS (FAB)m/z: 551 (MH'). Calcd. for C26H22N4010: C, 56.73; H, 4.03; N, 10.17%. Found: C, 56.59; H, 3.89; N, 10.01%. Preparation of the Diacid Chloride 4 The dicarboxylic acid 3 (5.5 g, 10 mmol) was refluxed with thionyl chloride (12 ml) under a nitrogen atmosphere for 2 h.The excess of thionyl chloride was distilled off and the acid chloride obtained was used without further purification, 1770 Preparation of the Polyamide 5a To a solution of the diacid chloride 4 (2.94 g, 5 mmol) in chloroform (20 ml), a mixture of ethylenediamine (0.34 ml, 5 mmol) and triethylamine (0.74 ml, 10 mmol) in chloroform (5ml) was added at 30 "C. The reaction mixture was stirred vigorously for 3 h and the solvent was removed under reduced pressure. The polymer obtained was dissolved in DMF (10 ml) and poured into an excess of water. The precipitated polymer was filtered off, washed with water and dried in a vacuum oven at 60 "C for 24 h to give 2.65 g (92%) of the polyamide 5a.qred: 0.19 dl g-'. IR v,,, (neat film)/cm-': 1656 (C=O, amide), 1535 and 1357 (NO,). 'H NMR (C2H6]DMSO) 6:1.4 (CH2 -CH,), 2.5 (NCH,), 5.0 (CH,), 7.6-8.9 (aromatic). Preparation of the Polyamide 5b The polyamide 5b was prepared by the condensation of the diacid chloride 4 (2.94 g, 5mmol) and p-phenelenediamine (0.54 g, 5 mmol) in the presence of triethylamine (0.74 ml, 10 mmol) in DMF (20 ml) at 32 "C for 6 h. The reaction mixture was poured into an excess of water and the precipi- tated polymer was purified after two reprecipitations followed by drying in a vacuum oven at 100°C for 12 h to give 2.8 g (85%) of 5b. qred: 0.21 dl g-'. IR v,,, (neat film)/cmP1: 1655 (C=O, amide), 1535 and 1357 (NO,). 'H NMR (C2H6]DMSO) 6 :2.5 (NCH,), 5.0 (CH,), 7.5-8.9 (aromatic).Steady-state Photolysis of the Polyamide 5b The polyamide 5b (500 mg) was dissolved in dry DMF (100 ml) and the solution was deaerated by purging it with dry argon for 15 min. It was then irradiated in an RPR (3000 A) photoreactor for 18 h and the reaction mixture was concentrated under vacuum and poured into an excess of methanol. The precipitated red-brown solid was redissolved in DMF and reprecipitated from methanol and then repeat- edly washed with methanol. The solid product obtained was dried at 60 "Cin a vacuum oven for 6 h to give 352 mg (70%) of 8. IR vmax (neat film)/cm-': 3200-2800 (broad, CO,H), 1655 (C=O, amide), 1570 (weak, N=N). 'H NMR (C2H6]DMSO) 6 :7.5-8.9 (aromatic).Lithographic Evaluation Photoresist solutions were prepared by dissolving the poly- amide 5a or 5b (10 wt.%) in N-methyl-2-pyrrolidone. The polymer solutions were then filtered through a 0.5 pm PTFE filter and subsequently spin-coated on silicon wafers to yield films ca. 1 pm thick. These polymer films were then subjected to prebaking at 100°C for 1h and were then contact exposed with a pre-calibrated Kodak step tablet, using an unfiltered low-pressure mercury lamp. The exposed films were developed in an aqueous solution of tetramethylamonium hydroxide (10%) for 1 min and rinsed with distilled water. Characteristic exposure curves were obtained by plotting the normalized film thickness remaining against the exposure dose. Results and Discussion The reaction pathways employed for the synthesis of the polyamides 5a and 5b is shown in Scheme 1.The IR spectra of the polyamides 5a and 5b indicated two strong absorption peaks at 1350 and 1530crn-' due to the nitro groups. The 'H and 13C NMR spectra of both the polymers were in good agreement with their respective structures. We could not determine the molecular weight of these polymers owing to their poor solubility in THF. However, the reduced viscosities J. MATER. CHEM., 1994, VOL. 4 CI I 1 2 t 3 reflux SOCI,2h r 1 L Jn 5a X= -CH2-CH2-5b X= +-Scheme 1 (qred) of both the polymers were determined in DMF at 30 "C and indicated that they were low-molecular-weight polymers. The thermal properties of these polymers were obtained from their TG curves and indicated that both the polymers are stable up to 200°C and that they began to decompose above this temperature.Phototransformationsof the Polyamides 5a and 5b Irradiation of the polyamides 5a or 5b in DMF at 300nm resulted in the formation of a deep red-brown solution, which on evaporation gave a low-molecular-weight product and a red-brown polymeric product. The low-molecular-weight product was identified as N-methylisophthalimide (6). Comparison of the viscosities of the starting polymers with their respective photoproducts revealed an increase in vis- cosity, in each case indicating that polymeric products were formed on irradiation. The IR spectrum of the polymeric photoproduct showed the absence of the characteristic absorp- tion peaks due to the nitro group. Considerable reduction of the absorption peak due to the amide group was observed. The IR spectrum also indicated substantial growth of the J. MATEK.CHEM., 1994, VOL. 4 broad absorption peaks at 3200-2800 cm-' which are indica- tive of the formation of carboxylic acid groups in the photop- roduct. A weak absorption at 1570 cm-I indicated the presence of an azo chromophore in the photoproduct. The two new absorption bands at 290 and 320 nm also indicated the formation of an azo chromophore. The 'H NMR spectrum of the polymeric photoproducts, obtained from 5a and 5b indicated the absence of the o-nitrobenzylic protons at 5ppm and the NCH3 protons at 3.15 ppm. Considerable reduction of the aromatic peaks at 6.8-8.8 ppm was also noted. The I3C NMR spectrum of the photoproduct revealed substantial reduction in the absorption peaks at 162.7 ppm due to the CONCH, group, at 148 ppm due to the aromatic carbon attached to the nitro group and at 41.4 ppm due to the o-nitrobenzylic carbon.Considerable reduction in the number of the aromatic peaks and the formation of a new carbonyl peak at 165.4ppm was also noted. All these observations led to the conclusion that the polymeric photoproduct (from 5a and 5b) could be an azo dicarboxylic acid polymer having the structure 8 which could arise through the pathways shown in Scheme 2. However, for the polyamide 9 complete degradation of the polymer back- bone occurred during photolysis.Comparison of these two observations indicates that even though the basic photochem- istry involved in both cases is the same, the subsequent reaction pathways are different. The mechanism of photo- transformation of 5a and 5b could involve the pathways indicated in Scheme2. In this case the initial photocleavage leads to the formation of the intermediate 7, having two u-nitrosobenzaldehyde moeities, which subsequently undergoes thermal dimerization resulting in the formation of the azo polymer 8. However, in for polymer 9, the initial photocleav- age generates the intermediate 10, which has only one o-nitrosobenzaldehyde group and gives the dimerized product 11 (Scheme 3). Photoresist Evaluation of Polymers 5a and 5b The phototransformations of the polyamides 5a and 5b indi-cate the presence of carboxylic acid groups in the photoprod- uct which brings about a considerable polarity difference between the unirradiated and irradiated polymers.This photo- induced polarity difference could be sufficient to recog iiise the irradiated and unirradiated portions of the polymer film by a suitable base developer, which prompted us to carry out detailed photoresist evaluation of the polyamides 5a and 5b. In order to gain a better understanding of the photochemical properties of the polymer films before carrying out the resist evaluation, thin films of the polymers 5a and 5b were prepared and irradiated for varying periods of time. Fig.1 shows the photochemical changes of the polyamide 5b as a function of irradiation time, on irradiation at 300 nm. The build-up of two new absorption bands at ca. 290 and 320 nm through the formation of an isobestic point at 273 nm is observed. The Jn Sb insoluble in aqueous base lhv 6 7 8 soluble in aqueous base, positive pattern Scheme 2 9 Scheme 3 J. MATER. CHEM., 1994. VOL. 4 h cn c.-c3 240 300 360 420 wavelengt hlnm Fig. 1 Photochemical changes of the polyamide film 5b after irradiation at 300 nm for (a)30 s, (b)60 s, (c) 2 min, (d) 4min, (e)8 min new absorption bands could be attributed to the formation of the azo chromophore, as indicated in Scheme2. The IR spectral changes of the film of 5b on irradiation, as a function of time are shown in Fig.2. The absorption bands at 1530 and 1350 cm-l, corresponding to the nitro group, disappear whereas there is an increase in the broad absorption at 3200-2800cm-' due to the formation of carboxylic acid group. In order to evaluate the photosensitivity of 5a and 5b,films of ca. 1 pm thickness were prepared on silicon wafers by spin- coating a solution of the corresponding polymers in N-methyl- 2-pyrrolidone. The characteristic photosensitivity curves of 5a and 5b are shown in Fig. 3, which indicates that the photosen- sitivities of these polymers are comparatively low under irradiation using an unfiltered mercury lamp. One of the reasons for such a low sensitivity could be the strong absorp- tion of the phototransformed azopolymer at the wavelength of exposure (> 300 nm).Thus, the photoproduct formed over the top of the polymer film could act as an internal light filter, protecting the inner part of the film and slowing down the overall phototransformation of the starting polymer film. 1336 1 10 100 1000 exposure energy1mJ cm-2 Fig. 3 Characteristic photosensitivity curves of the polyamides 5a(a) and 5b (b) However, these polymers are expected to be ideal positive- type photoresists for excimer-laser lithographic applications which will be the subject of further studies. Currently we are trying to synthesize several polyamides and polyesters with improved solubility and photochemical properties through structural modifications.Conclusions A novel phototransformation of polyamides containing o-nitrobenzylic chromophores on symmetrical positions of each repeating unit leading to azo polymers bearing carboxylic acid group ortho to the azo group is reported. Symmetrical incorporation of chromophores on the polymer backbone causes polymerization of the intermediate photoproduct, instead of the usual photodegradation as in the case of polymer 9, which contains only one o-nitrobenzylic chromo- phore per repeat unit. This study further illustrates that the overall reaction pathways during photolysis can be controlled by proper tailoring of chromophores in a polymer backbone. The photorearrangement induces a considerable polarity difference to the irradiated and unirradiated polymer due to the formation of carboxylic acid groups after photoirradiation.Changing the dissolution properties of polymers through polymer backbone rearrangement is a different approach from the conventional polymer-chain degradation or pendant func- tional group deprotection strategies in designing positive-type photoresist. The authors thank CSIR, Government of India and the Regional Research Laboratory, Trivandrum for financial sup- port of this work. A. A. thanks the Indian National Science Academy, New Delhi and the Japan Society for Promotion of Science, Tokyo, for the award of an exchange fellowship. This is document No. RRLT-PRU-45 from the Photochemistry Research Unit. References 1 G. Ciamician and P.Silber, Berichte, 1901,34,2040.\ 2 B. Amit and A. Patchornik, Tetrahedron Lett.. 1973,2205.LL3 V. N. R. Pillai, Synthesis, 1980, 1. 4000 3200 2400 1700 1100 500 4 D. H. Rich and S. K. Gurwara, J. Am. Chem. Soc., 1979,97,1575. wavenurnberlcm-' 5 A. Ajayaghosh and V. N. R. Pillai, J. Org. Chrm., 1987,52,5714. Fig. 2 1R spectral changes of the polyamide film 5b after irradiation 6 7 A. Ajayaghosh and V. N. R. Pillai, J. Org. Chcm., 1990,55, 2826. A. D. Broom and D. G. Bartholomew, Nucleic Acid Chem., 1976, at 300 nm for (a) 0, (b) 10 niin 2, 771. J. MATER. CHEM., 1994, VOL. 4 1773 8 9 10 11 12 13 14 A. Reiser, in Photoreactive Polymers: The Science and Technology of Resists, John Wiley, Chichester, 1989. E. Reichmanis, B.C. Smith and R. Gooden, J. Polym. Sci., Polym. Chem Ed., 1985,23, 1. H. Barzynski and D. Saenger, Angew. Makromol. Chem., 1981, 93, 131. E. Reichmanis, C. W. Wilkins, Jr. and E. A. Chandross, J. Vac. Sci. Technol., 1981,19, 1338. C. C. Petropoulos, J. Polyrn. Sci., Polym. Chem Ed., 1977,15, 1637. S. A. MacDonald and C. G. Wilson, IBM Res. Rep. No. RJ 3155 (38802), 1981. T. Iizawa, S. Wantanabe and T. Nishikubo, J. Polym. Sci., Polym. Lett. Ed., 1989, 27,411. 15 16 17 18 19 T. Iizawa, H. Kudo and T. Nishikubo, J. Polym. Sci., Polym. Lett. Ed., 1991,29, 1875. F. M. Houlihan, A. Shugard, R. Gooden and E. Reichmanis, Proc. SPIE, Advances in Resist Technology and Processing V, 1988,920, 67. R. G.Tarascon, E. Reichmanis, F. M. Houlihan, A. Shugard, and L. F. Thompason, Polym. Eng. Sci., 1989,29,850. T. Mathew, A. Ajayaghosh, S. Das, P. V. Kamat and M. V. George, J. Photochem. Photobiol. A: Chem., 1993,71,181. A. Ajayaghosh, S. C. George and M. V. George, J. Chem. SOC., Chem. Commun., 1994,423. Paper 4/049 1 1 J; Received 10th AuguJit, 1994

ISSN:0959-9428    

DOI:10.1039/JM9940401769

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

J. MATER. CHEM., 1994,4(12), 1775-1783 Sulfonated Polyaniline Films as Cation Insertion Electrodes for Battery Applications Part 1 -Structural and Electrochemical Characterization Cesar Barbero, Maria C. Miras, Bernhard Schnyder, Otto Haas and Rudiger Kotz* Electrochemistry Section, Paul Scherrer Institute, CH-5232Villigen PSI, Switzerland Sulfonated polyaniline (SPAN) was synthesized by sulfonation of polyaniline (PANI) base with fuming sulfuric acid. Thin films were cast from polymer solutions in basic media. The polymer films were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible-near-infrared spectroscopy, scanning electron microscopy (SEM) and cyclic voltammetry. XPS in combination with FTIR showed that the preparation procedure led to ca.47% sulfonation of an otherwise unchanged polyaniline backbone. The NIR spectra of SPAN films showed a polaron band at higher energies than with polyaniline. This is in agreement with the lower conductivity of SPAN as compared with polyaniline. SEM micrographs of the SPAN films showed a compact globular morphology. Electrodes modified with thin SPAN films exhibited two redox steps, both in aqueous and in non-aqueous electrolytes. The specific charge stored in SPAN films was found to be ca. 37 A h kg-' in aqueous solution (only the first redox step) and ca. 68 A h kg-' in non-aqueous media (both redox steps). A practical SPAN-Li battery could have 50% more specific energy than a PANI-Li battery.The optical spectra of SPAN films exhibited bands at 310, 450 and 750 nm, the intensities of which changed during the redox process. The absorption coefficients of SPAN (emeraldine base state) solutions had values of a =410 at 31 3 nm and a =239 at 563 nm. The suitability of SPAN for use as a cation-insertion material for battery and electrochromic applications is discussed. Polyaniline (PANT) is one of the most promising conductive polymers for battery applications owing to its rather high theoretical specific charge, high conductivity (> 1 S ern-') and stability and because it has an inexpensive monomer.' Although PANI-Li batteries are commercially available,' their specific energy is relatively low (<30 W h kg-l) as compared with that for conventional systems.During electrochemical oxidation/reduction of the PANT polymer matrix, positive charges are created/neutralized within the film. In order to maintain the film's electroneutral- ity, ions have to be exchanged with the electrolyte s~lution.~ Previous studies of PANI showed that anions and protons are exchanged in aqueous solution^,^,^ whereas in non-aque- ous media anions are mainly used as the charge compensating Pure cation exchange by the polymer is necessary for its use in cation-transfer batteries. The transformation of an anion-exchanging polymer into a ca tion-exchanging polymer can be achieved by irreversible incorporation of negatively charged groups into the polymer. Different procedures can be used, such as polymerization of the monomer in the presence of a polyelectrolyte [e.g.poly-(styrene ~ulfonate)~ J or the preparation of composites [e.g. PANI-Nafion']. In order to keep the stored specific charge at reasonably high values, the amount of mass added should be low. One way to achieve this is by covalent bonding of light anionic groups to the polymer backbone. It was shown that sulfonate groups can be linked to the PANI backbone by sulfonation of the polymerlo to give partially (50%) sulfonated polyaniline (SPAN). It was also demonstrated that films can be produced from polymer solu- tions." Some of the properties of the sulfonated polymer itself have already been described in the In this work we describe the physical and electrochemical characterization of SPAN films and solutions.The parameters in polymer synthesis and film formation that are relevant to applications are discussed. Information about stability, specific charge capacity and electroactivity is necessary when using the polymer in electrochemical systems, such as batteries and electrochromic devices. In further work,14 the ion exchange properties of SPAN as studied by probe beam deflection and electrochemical quartz crystal microbalance, will be reported in detail. Experimental Electrochemistry A conventional three-electrode cell was used to perform the electrochemical investigations. The counter electrode was a Pt plate, the reference electrode a saturated calomel electrode (SCE).The working electrodes were SPAN-modified Au films on glass or SPAN films on GC plates (glassy carbon), the reverse side of which was covered with an inert varnish (Lacomit). The electrochemical experiments were cor itrolled by use of a BAS lOOa (Bioanalytical Systems) potentiostat. The redox charge was obtained by integration of the current- potential data. Acetonitrile (Aldrich, HPLC grade) and propyl- ene carbonate (Fluka, puriss.) were used as received. The electrolyte salts were dried under vacuum. All aqueous solu- tions were prepared with ultrapure water and analytica 1 grade reagents. All potentials are quoted uersus the SCE. X-Ray Photoelectron Spectroscopy (XPS) The XPS spectra were measured with a Kratos IS 300 electron spectrometer using non-monochromatized Mg-Ka radiation (1253.6 eV).The fixed analysis transmission mode was chosen. The vacuum in the analysis chamber was always greater than 2 x Torr. The samples (SPAN films on Au) were investigated in the pristine state, because even slight Ar sputtering was found + to alter the composition significantly. Scattering cross-sections for quantitative analysis were taken from the 1iterat~re.l~ No charging effects were observed. Fourier-transform Infrared (FTIR) Spectroscopy A Perkin-Elmer (PE) 2000 FTIR spectrophotometer was used to measure the ex situ IR spectra. Two arrangements were used: transmission and reflectance. For transmission measure- ments the polymer was deposited onto an Si wafer.The spectra of these polymer films were recorded with a bare Si wafer as the reference using a PE automatic sample shuttle. For reflectance measurements the polymer was deposited onto Au film on glass. The measurements were made at 70" with p-polarized light in a Harrick variable-angle reflectance accessory. Electrochemically treated films were obtained by cycling the potential of modified electrodes in the electrolyte solution between -0.2 and 0.5 V us. SCE. In order to obtain films in different redox states, the electrodes were kept at the desired potential until the current had decayed to negligible levels, then they were withdrawn from the solution and their spectra measured. The solution was carefully deaerated by Ar bub- bling and then maintained under an argon blanket.The electrodes were always removed from the solution under potential control and quickly dried in an argon stream. Ultraviolet-VisibIeNear-infrared (UV-VIS-NIR) spectroscopy Spectra of SPAN solutions were recorded in quartz cells (Suprasil, Hellma) of 1 cm optical pathlength. Spectra of SPAN films were recorded with the polymer deposited onto quartz plates. For studies of the electrochromism of SPAN, thin films were deposited onto transparent electrodes [indium-tin-oxide (ITO), 25 SZ cmP2; Balzers]. The electrodes were washed with toluene and ethanol and the contact was made with electrodag. The electrodes were mounted in a Kel-F holder. All optical absorption measurements were carried out with a Cary 2400 UV-VIS-NIR spectrophotometer.Scanning Electron Microscopy (SEM) Scanning electron micrographs were recorded from SPAN films deposited onto a polished Si wafer. A Hitachi 9410 scanning electron microscope was used. Polymer Preparation All chemicals used were of reagent grade. PANI Polyaniline salt was prepared according to the method of McDiarmid et a1.16 A solution of aniline in 1 moll-' HC1 was mixed with an equimolar amount of the oxidant (ammonium persulfate). Polyaniline base (I j was obtained by treating the polyaniline salt with NH,OH solution (10%) for 24 h with continuous stirring. As an alternative route, commer- cial polyaniline (Versicon, Allied Signal Corp.) in salt form was subjected to the treatment with NH,OH solution to obtain polyaniline base.SPAN The polyaniline sulfonation procedures utilized have pre- viously been described in the and are only briefly summarized below. Emeraldine base 0.5 g (I)was finely ground and dissolved in 40 ml of cool (<5 "Cj fuming sulfuric acid (30% SO, in H2S04) to yield a dark purple solution (11). The sulfonation was carried out at 5°C with constant stirring in a 500 ml closed Erlenmeyer flask for 2 h. The colour of the solution changed from dark purple to dark blue when sulfonation was complete (111 in Scheme 1). The liquid was then added, in small portions, to 200ml of methanol that were kept cooled by an ice-bath. Upon neutralization of the acid, SPAN (IVj precipitates out. It was found that the addition of acetone, as recommended by Yue et al.," was J.MATER. CHEM., 1994, VOL. 4 detrimental to polymer precipitation. The solution was filtered and the filtrate was washed with several 50ml portions of methanol until the pH of the washings was neutral. The polymer (IV) was then dried under vacuum at 50 "C for 48 h and stored in a desiccator. The average yield was below 20%. It has been reported previo~sly,'~ that the yield and conduc- tivity of the sulfonated polymer reached maximum values after 1 h of sulfonation, then decreased. We tried sulfonation at ambient temperature (20°C) using a reaction time of 1 h, the average yield was ca. 60%. The resulting polymer dissolved faster in ammonia solution, and the resulting films were more homogeneous (optical microscopy).The sulfonation procedure is summarized in Scheme 1. First the PANI base was dissolved in concentrated sulfuric acid. The imine nitrogens became protonated with formation of polyaniline sulfate salt. The subsequent attack of the electro- philic agent (SO,) occurred in the uncharged units, which have higher electronic density. Therefore a limit of 50% sulfonation was obtained with this medium. Two side reactions could occur in the strongly acid media: (i) breaking of the nitrogen bonds with formation of quinones and (ii) cross-linking of different chains; both reactions would be promoted by the presence of SO,. Preliminary data on the molecular weight of SPAN" suggested that both reactions occur. The starting material had a narrow dispersion of molecular weight but yielded a mixture of SPAN polymers with larger dispersion than PANI.Longer sulfonation times would allow side reac- tions to occur. After sulfonation, the solution of SPAN in H2S04 was added to methanol. The purpose of this step was to neutralize the remaining SO, and H,SO, with the methanol by formation of methyl sulfates without excessive heat release. The resulting solid was SPAN in its zwitterion state, which was insoluble in methanol and therefore precipitated out. SPAN Solutions Two milligrams of SPAN (IV) were dissolved in 10ml of 0.1 moll-' (or 1 moll-lj NH,OH. As discussed before, poly- mer samples prepared by the conventional procedure dissolve slowly (1-2 h) whereas samples prepared by the modified procedure dissolve instantaneously.The polymer was con- verted to the salt, [C12HxN2] SO,-NH,+, which was soluble in water and gave a dark blue solution. The properties of the solutions changed on storage (see below). Therefore fresh solutions were prepared before use. Solutions of the leucoemeraldine form of SPAN were pre- pared by reduction of SPAN solution with hydrazine (1% in water). The slow reduction was accompanied by a loss of colour and was complete after 2 h. SPAN Films These were cast on appropriate substrates by pouring a portion (typically 0.1 ml) of the polymer solution onto the substrate and drying under an IR lamp. The ammonium salt of SPAN decomposed upon heating, releasing NH,, which was followed by evaporation of the solvent.The resulting film was obtained in its zwitterionic form ([C12H8N2H2]+ -SO,-j, which was insoluble in water (at pH <8). The films were stable in air for several months and had a reproducible electrochemical response. We found that films obtained by spontaneous drying of the solution in air (even in a dry atmosphere) have no reproducible electrochemical response. Results and Discussion XPS The XPS investigations were performed with SPAN films deposited onto gold substrates. The electrodes were first cycled J. MATER. CHEM., 1994, VOL. 4 (1) pdyaniline (emeraldine base) 30%SO3 In HSO,1 (11) polyanilinesolution (vW) more stable structure (separated radical cations) (111) SPAN solution (dark Hue) fd-"q=y&yj;so; (Iv) SPAN (green powder) 9+\/ \/ N-\/ *+ \/ Scheme 1 in 1 mol I-' HC1 to assure that the film composition corre- sponded to the electrochemically active material and not to the virgin state after sulfonation.For the sake of comparison, XPS of a virgin film was also carried out. In addition to the survey spectrum the emission peaks of S 2p, N Is, C Is, C12p and 0 1s were investigated. The resulting spectra are reproduced in Fig. 1, both for the sample as prepared and for the same sample after electro- chemical cycling. For the latter the electrode was removed from the electrolyte in its oxidized state. The main difference between the spectra are the reduced intensities of 0 Is, N 1s and S 2p emission in the spectrum recorded after electrochemi- cal cycling.This observation could be explained by the presence of residual (NH4),SO4 in the as-prepared film, which might originate from the sulfonation step and the subsequent precipitation. After electrochemical cycling the contamination was found to have disappeared from the film. The contribution of these species to the spectra of N 1s and S 2p was on the high binding energy side at binding energies of 402 eV for N and at 168.5 eV for S. These binding energies correspond to NH4+ and species." In addition, the presence of NH4+ species was indicated by the low C:N ratio of 3.2 (theoretical ratio 6) in the untreated film. The S :N ratio of the untreated film was higher than that of the sample after cycling, indicating additional SO,2-retention.For the sample after electrochemical cycling, only one S peak occurred at a binding energy of 167.8 eV, typical of SO3-groups." The nitrogen peak was observed at 399.5 eV with a shoulder towards higher binding energies at 401.7 eV, which is in agreement with previous investigations.20 This shoulder indicated positively charged nitrogen atoms. A weak C12p peak could be observed for some samples at a binding energy of 200.4 eV, indicating C1- retention.15 The S :N ratio, which corresponds to the degree of sulfon- ation, was determined for five independent samples. The average degree of sulfonation was about 0.47 0.07%, the average C1- :N ratio was between 0.0 and 0.1.The C :N ratio was found to be 6.5 f2, while the 0:S ratio was 4.5 & 1, indicating roughly one benzene ring per nitrogen atom and some oxygen, probably originating from H20 and from the SO3-groups. The XPS results clearly indicate up to 47% sulfonation of PANI. In the half-oxidized state most of the charge was compensated by the SO3-groups, and a small incorporation of C1- was necessary for compensation of the remaining charge. The corresponding formula for the polymer unit can therefore be written as -{ [(C6H3NH+*S03-)0.47-(C6H4NH+ -C1-)o.03]-(C6H,NH)o.51-. Because the films were removed from the electrolyte in the oxidized state, this corresponded to an almost total compensation of the radical cation charge by the sulfonate group.FTIR The structure of the polymer films was investigated by trans- mission and reflection FTIR in the range 450-6500cm-'. The transmission spectrum of the SPAN film (Fig. 2) agrees quite well with the one reported previously (limited to the region 1700-500cm-1) for bulk SPAN.l2 The assignment of the vibrational bands2' in SPAN is described in Table 1. J. MATER. CHEM., 1994, VOL. 4 as prepared cycled01s t I10.0 I: *. I6.0 2.0 ' i, 540 530 520540 530 N 1s11 3.0 520 .r 1 0 t . G' . 0 . It 410 400 390 410 400 390 c 1s 6.0 4.0 2.0 0 295 285 275 295 285 275 S 2P 2.0 1.5 I' 1.o ?f b 1. I 0.5 180 170 160 180 170 160 binding energylev Fig. 1 XPS spectra of SPAN film samples on Au substrate as prepared and after electrochemical cycling in 1moll-' HCI For comparison, a similar assignment was made for a PANI reflectance spectra of SPAN films in the reduced and oxidized film.The main difference between SPAN and PANI was the state. By comparing Fig. 3 with Fig. 2 it can be seen that most presence of bands at 1082cm-', 1024cm-' and 618 cm-l, parts of the spectra are identical. However, a band at ca. attributed to the SO3-group in SPAN. The occurrence of 1450cm-1 is present with the virgin sample that is not seen two bands, attributed to SO3-, between 1000cm-' and with the electrochemically treated sample. This band was 1100cm-' indicated binding of the SO3-group to the benzene assigned to the NH4+ions that remain in the polymer together ring2' The FTIR reflectance spectrum of a virgin SPAN film with trapped sulfuric acid.Upon cycling in aqueous solution (Fig. 2) was not significantly different from the transmission the salt dissolved and the band disappeared. The correspond-spectrum. ing band for NH,+ at 3400cm-' overlapped with the CH Electrochemically treated samples were cycled in 1 moll-' and NH bands of the polymer. The presence of these contami-HC1 solution before the FTIR measurements were made in nants was deduced from the XPS results described above. order to assure equilibration of the film. Fig. 3 shows the By comparing the two spectra in Fig, 3, it can be seen that J. MATER. CHEM., 1994, VOL. 4 0.30 0.20 8 s e8 a a 0.10 0.00 400 1400 2400 3400 wavenumbehm-' Fig.2 FTIR spectra of SPAN films cast from aqueous solution onto: (a) an Si wafer (measured by transmission); and (b) a gold electrode (measured by reflection, 70" with p-polarized light) Table 1 Assignment of 1R absorption bands in SPAN ' ~~~~~~~~~~ IR band/cm bond group vibration mode 3235.2 N-H" aromatic amine stretching 3066.7, 2862 C-H" aromatic stretching 1 600.3 C=Nb quinoneimine stretching 1508.0 C-cb aromatic stretching 1451.7 NH,' 1425.9 C=Cb aromatic stretching 1311.1 C-N' secondary aryl amine bending 1176.2 C-Hh in-plane bending aromatic 1081.8, 1024.2 s=o sulfonate stretching 823.7 C-H' out-of-plane bending aromatic 707.9 c-s aromatic stretching 617.8 s=o sulfonate stretching "Also present in PANI, but difficult to see in the spectra because bands overlap with the broad conduction band of PANI.'Also present in PANI. the same bands are present in the oxidized and reduced state. However, there are differences in the band intensities. The absorbance above 4000 cm-' is significantly higher in the oxidized than in the reduced state. Such absorption corre- sponded to the tail of the NIR band of the polaron,22 which was only present in the emeraldine state of the film. Differences could also be observed in the region 1700-1400 cm-' (see insert in Fig. 3). The intensity of the band at ca. 1600 cm-' increased on oxidation, while the intensity of the band at 1510 cm-' decreased.The band at 1510 cm-' was attributed to the C-C vibration of the benzenoid ring.21 The vibration at ca. 1600 cm-' was attributed to the C=N of the quinone- imine ring." On oxidation the amine (containing aromatic C-C bonds) was partially converted to quinoneimine (con- taining C=N bonds). The insert in Fig. 3 shows that the C=N band is located at ca. 1620cm-' in the reduced state but seems to shift on oxidation towards ca. 1580cm-'. It is not clear whether the band actually shifts or whether a third band appears at 1580cm-' while the one at 1620cm-' remains unchanged. A similar variation of band intensity with the oxidation state was observed for PANI.22 Under the experimental conditions described, the reflection spectra of PANI filrns was measured in the reduced and oxidized state.The band at 1510cm-', corresponding to the benzenoid ring, decreased on oxidation and the band at ca. 1600cm-' (quinoneimine) increased on oxidation. The apparent band shift is also present for PANI. The background absorption below 4000 cm-' increa.;ed on oxidation of PANI, as for SPAN. However, a new band appeared at ca. 0.5 eV (4000 cm-'), corresponding to free carrier absorption. In SPAN such a band exists at energies above 1eV (8000 cm-I). The difference could be explained by a higher localization of the charge carriers in SPAY due to the steric effect of the sulfonate group. The lower mobility of the charge carriers makes SPAN less conductive than PANI." The FTTR investigations led to the conclusion that sulfon- ation of PANI was' achieved with an otherwise unchanged polymer structure.UV-VIS-NIR Spectroscopy Solutions Optical spectra of the polymer salt form were recorded in the solution used for film formation (0.1 mol I-' NH,OH). The spectra revealed bands at 317 nm and 563 nm [Fig. 4(b)]. These bands corresponded to the anionic (-SO,-) form of the polymer. The spectra are similar to those previously reported for the sodium salt of SPAN in water." The band at 317 nm was assigned to the n+n* transition of the aniline ring.14 The band at 563 nm was assigned to the 'exciton' transition of the quinone and was related to intrachain hopping.23 To confirm this assignment, the reduced form of SPAN was produced in solution. The UV-VIS spectrum [Fig.4(a)] revealed a single band at ca. 320 nm. This agreed with the spectra for the leucoemeraldine base of PANI that contain only the band due to the n+n* transition. The optical absorption obeys the Beer-Lambert law between 20 and 200 pmol I-'. This fact allowed the calculation of the specific absorption coefficient of the polymer chmmo- phores. The band at 313 nm has an absorption coefficient of J. MATER. CHEM., 1994. VOL. 4 400 1200 2000 4000 6000 wavenurnber/crn-' Fig. 3 FTIR spectra of SPAN films at different redox states: (a) reduced (emersed at -0.2 V us. SCE); and (h)oxidized (emersed at +0.5 V 1:s. SCE). The electrolyte solution was 1 moll-' HCI. The insert shows the region between 1700 and 1400 cm-l.1.0 r 0.8 8 0.6 1 8 .na 0.4 0.2 0 300 400 500 600 700 800 wavelengthhm Fig. 4 UV-VIS absorption spectra of SPAN solutions: (a)leucoemer-aldine state (reduced): and (b)emeraldine state (oxidised) a =410, for that at 563 nm a =239. By assuming a molecular weight for the polymer unit of 133 g mol-I (one aniline unit with 50% sulfonation), the molar absorption coefficients are ~=5400at 313 nm and ~=3200 at 563nm. These values indicate forbidden transitions (e< 10OOO).24 The value is low compared with the extinction coefficient, c;1= 1.6 x lo5cm-(corresponding to E = 10000),25determined for solid-state PANI at 320 nm. Film Optical spectra of the polymer films were measured (in the range 200-2600nm) on thin films of SPAN deposited onto quartz plates from aqueous solution.The PANI film was deposited from an emeraldine salt dispersion.26 The spectra in the UV-VIS range agreed with those reported previously.',' The spectrum of SPAN exhibited bands at 320nm and 850 nm and a shoulder at 440 nm [Fig. 5(a)]. The band at waven umber/crn-' 10000 5000 4000 2.60 1.95 1.30 n a 0.65 0.00 200 lo00 1800 2600 wavelength/nrn Fig.5 UV-VIS-NTR spectra of (a) SPAN: and (h) PANI films deposited onto quartz plates. SPAN was deposited from aqueous solution, PANI from a propan-2-01 dispersion. 320 nm corresponded to the n+n* transition of the aromatic ring. The shoulder at 440 nm was associated with the localized radical cations of aniline units.The band at 850 nm was broad and related to absorption by the metallic polarons.2s The spectrum did not reveal the band at ca. 1600nm present in the spectrum of PANI [Fig. 4(6)]. It is likely that such a band was shifted to higher energies and overlapped with the band at 850 nm. SEM The SEM micrograph of a SPAN film on Si (Fig. 6) revealed a globular structure with features of cn. 20 pm in size. The morphology differed significantly from that of electrochemi- cally deposited PANI,27 which has a fibrillar structure. The SPAN-film morphology was similar to that of PANT films J. MATER. CHEM., 1994, VOL. 4 Fig. 6 Scanning electron micrograph of a SPAN film deposited onto an Si wafer deposited from aqueous dispersions28 and from solutions in N-methylpyrr~lidone.~~Based on these SEM results, the porosity of the SPAN films was probably lower than that of electrochemically deposited PANI.Electrochemically deposited PANI grows around nuclei, favouring fibre forma- tion, whereas deposition from solutions takes place over the whole surface by a precipitation reaction that creates com- pact layers. Cyclic Voltammetry Films prepared as described in the experimental part were tested by cyclic voltammetry in aqueous and non-aqueous solutions. Aqueous Solutions The electrochemical behaviour of films in aqueous solutions was studied using several concentrations (0.1-4 moll-') of strong acids (HC1, H2S0,, HClO,, CF,SO,H). After immer- sion of the electrode, several (> 10) cycles of between -0.2 and 0.5 V us.SCE at 100 mV s-' were performed in order to equilibrate the film with the electrolyte. A typical cyclic voltammogram recorded in 0.1 moll- HC1 between -0.2 and 0.85 V us. SCE is shown in Fig. 7. It agrees with those previously reported." SPAN exhibited two redox processes (at 0.15 and 0.7 FS. SCE) as did PANI. The maximum currents of both peaks were linear functions of the scan rate (10-250 mV s-I), indicating that the redox sites in the layer 0.8 4 0.4 E =at L2 0.0 -0.4 0.0 0.4 0.8 electrode potentiaVV vs. SCE Fig. 7 Cyclic voltammogram of a SPAN film on GC in 0.1 moll-' HCl. Scan rate: 50 mV s-'. -0.4 0.0 0.4 0.8 electrode potentialN vs. SCE Fig.8 Cyclic voltammogram of a SPAN film on GC in 0 1 mol I-' LiC104-ACN. Scan rate: 50 mV s-'. were in thermodynamic equilibrium with the electrode poten- tial during the voltammetric excursion. Although PANI showed no electroactivity in solutions of pH<4, SPAN showed a clear electroactivity up to pH 7. At pH 7 the two peaks overlapped yielding a broad wave at ca. 0.5 V us. SCE. Non-aqueous solutions The electrochemical response of SPAN in non-aqueous elec- trolytes was also investigated. After immersion of the electrode in the electrolyte. several (~20)cycles of between -0.2 and + 1.0 V us. SCE were performed to achieve equilibration of the polymer film with the solution. The redox charge increased significantly during this period, and the peaks became more clearly defined.Fig. 8 shows the cyclic voltammogram obtained in acetonitrile- LiC104. The two redox processes present at 0.2 and 0.95 V us. SCE were broader than those in aqueous solution Electrochemical Stability of the Films The stability of the polymer towards oxidation/reductmon was tested in aqueous solution, by recording the charge during cycling between -0.2 and 0.5 V us. SCE. Some loss of charge occurred, which depended on the pH of the soluticm. The percentage loss of redox charge after 1000 cycles (scan rate: 100 mV s-l) at different proton concentrations is shown in Fig. 9. The polymer stability decreased with increasing H+ concentration. It is known that the polymer is soluble in concentrated acids,' therefore dissolution of the films at high H+ concentration could explain their instability.Cycling the electrode in aqueous solution between -0.2 and 0.8 V us. 8 20 0)F2 10i0 3 0 1 ............. . ......._..........................................................a.......... 0.0001 0.1 1 2 4 proton concentration/mol r1 Fig.9 Percentage loss of redox charge of SPAN films after 10oO cycles in solutions with different proton concentrations SCE induced strong degradation with almost total loss of charge after 1000 cycles. In non-aqueous solutions the loss of charge during cycling between -0.25 and 1.0V us. SCE at 50 mV s-' was only 3% after 1000 cycles. Stability of the Solutions It was found that the properties of SPAN solutions changed during storage.When the solution was stored for more than one week, the bands in the UV-VIS spectra shifted towards higher energies. A possible explanation was breaking of some aminic bonds with shortening of the SPAN chains. The breaking of the chains could occur by hydrophilic attack of water molecules on the aminic bonds. Shorter chains have a reduced delocalization of electrons, which increases the transition energy.13 Possible changes occurring in aqueous SPAN solutions with time were also studied by casting films from fresh and old (3 weeks) solutions. The IR spectra showed no significant differences in the region between 1800-450 cm-l, suggesting that no new compound was formed.However, the intensity of the free carrier absorption above 4500 cm-decreased significantly. This decrease could be related to a lower conductivity of the film deposited from an old solution. The electrochemical response of films deposited from old solutions was characterized by a sluggish voltammogram with a large separation of anodic and cathodic peaks. Polymer solutions in propan-2-01 media suffered no notice- able changes, indicating that the stability problem might be resolved by film deposition from alcoholic solutions. The increased stability in alcoholic solutions supported the idea that the attack by water molecules (present only in low concentration in alcoholic solutions) caused the degradation reaction. Specific Charge The amount of polymer deposited could be controlled by the amount and concentration of the solution used to form the film.The calculation procedure for the specific charge assumed that none of the material deposited dissolves into the electro- lyte. If it did, the film mass would be overestimated and the specific charge underestimated. Therefore, the values of specific charge reported probably represent lower limits. Aqueous Solutions The variation of the charge with the amount of material deposited is shown in Fig. 10 for polymer prepared by the modified procedure. The value for specific charge was obtained from the slope, thus any contribution of the background charge was avoided. The redox charge was measured in 1 moll-' HCl solution in H20 by cycling the electrode between -0.2 and 0.5 V us.SCE at 10 mV s-'. Lower scan rates gave the same charge. A value of 37f2 A h kg-I was deduced for the first peak of SPAN (the second process could not be used for charge storage in aqueous solution because the polymer degraded significantly, as discussed above). The fact that the polymer prepared by the conventional procedure had a lower specific charge (22A hkg-')' suggested that further modifications of the preparation procedure might boost the value even further. Non-aqueous solutions The charge was measured by cycling a SPAN film (modified procedure'') between -0.5 and 1.0V us. SCE at 10mV s-' in non-aqueous electrolyte (ACN-LiC10,). The plot of redox charge against the amount of polymer was linear (Fig.10). J. MATER. CHEM., 1994, VOL. 4 0 20 40 60 80 polymer mass/pg Fig. 10 Dependence of redox charge of a SPAN film on the amount of polymer deposited. Aqueous solution (1 moll-HCl): charge measured during cycling between -0.2 and 0.5 V cs. SCE at a scan rate of 10 mV s-'. Non-aqueous solution (0.5 moll-' LiC10,-ACN): charge measured during cycling between -0.2 and 1.0 V z's. SCE at a scan rate of 10 mV s-'. (A)LiClO,-ACN; (0)HC'l-H20. 0.5 0.4 g 0.3 2P n(II 0.2 0.1 I I I I 300 400 500 600 700 800 wavelengthhm Fig. 11 Evolution of the UV-VIS spectra of a SPAN film on IT0 with applied potential (V us. SCE). Electrolyte: 0.4 mol 1-' NaC10,-0.1 moll-' HC10,. From the slope of the plot a value for the specific charge of 68k5 A h kg-' (both redox steps) was obtained.Films of polymer prepared by the conventional procedure" gave a value for specific charge of 35 A h kg-' in the same media. With the measured value of specific charge of SPAN films, the calculation for the specific energy of a SPAN-Li battery could be made; assuming that the SPAN film exchanged only cations during oxidation/reduction, as demonstrated else-where.14 The mass balances of the active battery materials and the electrolyte are summarized in Table 2. The amount of solvent was calculated for 2 moll-' LiC10, solution with Table 2 Mass balance for a rechargeable Li-SPAN battery (not including current collectors, separator and cell container) component mass equivalent/g (mol e-)-' SPAN 394 LiClO, (0.5 MW) 53.75 Li (0.5 MW) 3.5 electrolyte 60 (solvent +LiClO,) total 511.25 (ca.52 Ah kg-'+ca. 130 W h kg-I) J. MATER. CHEM., 1994, VOL. 4 a density of ca. 1.2 g cm-3 and with an approximated volume, which neglected any swelling of the polymer film upon immer- sion in the electrolyte. The overall specific charge was 52 A h kg-'. By using an average discharge voltage of 2.5 V, a 'semi-empirical' specific energy of ca. 130 W h kg-' was estimated. During previous work,6 a value of 87 W h kg-' was obtained for the specific energy of a PANI-Li cell (using both redox steps). The specific energy for a SPAN-Li battery was therefore ca. 50% higher than a PANI-Li battery.Although the measured specific charge of the polymer electrode was significantly lower, the reduced contribution of solvent to the total mass of the battery would permit a net gain of specific energy of the battery. Electrochromic Properties A potential application for conducting polymers is in elec- trochromic devices. While it is known that PANI can be used for that purpose,3o no quantitative study has previously been performed on SPAN. The evolution of the SPAN spectra with applied potential was investigated (Fig. 11). Three bands were observed at 750, 450 and 310 nm. The band at 310 nm was attributed to the n-+n* transition of the aniline ring23 and was hypsochromically shifted relative to that of polyaniline. The hypsochromic shift of the UV band in SPAN (relative to polyaniline) was attributed to the inductive effect of the sulfonic groups in the aromatic ring.'' The band at 450nm was assigned to the localized cation radical.25 The absorbance at this wavelength first increased with oxidation, then decreased.This corresponded to the initial formation of radical cations that disappeared upon further oxidation. The band at 750 nm corresponded to the metallic polaron.22 The absorbance at 750 nm increased continuously with oxidation and shifted to higher energies in the NIR region. The behav- iour of the bands in SPAN was very similar to polyaniline. The most widely used electrochromic material,31 tungsten oxide, bleaches on oxidation and cations are inserted; SPAN bleaches on reduction with cation expulsion.A 'rocking chair' configuration could therefore be assembled in which a tung-, sten oxide electrode would be the negative electrode and SPAN the positive electrode in the coloured state. As the electrochromic effects are complementary, a high-contrast device could be achieved. Conclusions SPAN was produced by chemical sulfonation of PANT. The best procedure for this used a short (1 h) reaction time at room temperature. The polymer obtained dissolved faster in basic media and more homogeneous films with a higher charge density could be cast from these solutions. XPS investigations suggested an average degree of sulfon-ation of 47%. FTIR results indicated that the sulfonation did not significantly alter the PANI backbone but induced a higher localization of the charge carriers. SPAN solutions in aqueous ammonia changed with time and this could be seen from a hypsochromic shift of the absorption bands, a decrease of absorption, a decrease in the intensity of the free carrier absorption in the IR and a more sluggish electrochemical response for films formed from old solutions. Alcoholic solutions were stable.SPAN was electroactive in non-aqueous media and in aqueous solvent up to pH 7. The charge density was at least 35 A h kg-' (first redox step) in aqueous solution and more than 65 A h kg-' (both redox steps) in non-aqueous solution. A SPAN-Li battery could yield up to 50% more specific energy than a PANI-Li battery. The films were distinctly electrochromic.The evolution of the UV-VIS spectra with applied potential was similar to that of PANT. Professor E. M. Genies is gratefully acknowledged for helpful discussions and making unpublished results available. The project was financed by the Swiss National Science Foundation, Grant No. 20-32504.91. References 1 E. M. Genies, M. Lapkowski and C. Tsintavis, New J. Chem., 1988, 12, 181. 2 T. Matsunaga, H. Daifuku, T. Nakajima and T. Kawagoe, Polym. Adv. Technol., 1990, 1, 33. 3 W. S. Huang, B. D. Humphrey and A. G. MacDiarmid, J. Chem. Soc., Faraday Trans., 1986,82,2385. 4 C. Barbero, M. C. Miras, 0. Haas and R. Kotz, J. Electrochem. SOC.,1991, 138,669. 5 H. Daifuku, T. Kawagoe, N. Yamamoto, T. Ohsaka and N.Oyama, J. Electroanal. Chem., 1989,274,313. 6 J. Desilvestro, W. Scheifele and 0. Haas, J. Electrochem. Soc., 1992,139,2727. 7 C. Barbero, M. C. Miras, R. Kotz and 0.Haas, Synth. Met., 1993, 55-57,1539. 8 Y. Kang, M-H. Lee and S. B. Rhee, Synth. Met., 1992,52,319. 9 D. Orata and D. A. Buttry, J. Electroanul. Chem., 1988,257,71. 10 J. Yue and A. J. Epstein, J. Am. Chem. Soc., 1990,112,2800. 11 J. Yue, Z. H. Wang, K. R. Cromack, A. J. Epstein and A. G. MacDiarmid, J. Am. Chem. Soc., 1991,113,2665. 12 J. Yue, A. J. Epstein and A. G. MacDiarmid, Mol. Cryst. Liq. Cryst., 1990, 189,255. 13 Y. Cao, S. Li, Z. Xue and D. Guo, Synth. Met., 1988,16,305. 14 C. Barbero, M. C. Miras, R. Kotz and 0. Haas, unpublished work. 15 J. J. Yeh and I.Lindau, Atomic Data and Nuclear Data Tables, 1985,32,1-155. 16 A. G. MacDiarmid, J. C. Chiang, J. C. Richter, A. F. Richter, N. L. D. Somarisi and A. J. Epstein, in Conducting Polymers, ed. L. Alcacer, Reidel, Dordrecht, 1987, pp. 105-120. 17 J. Yue, G. Gordon and A. J. Epstein, Polymer, 1992,33,4410. 18 E. M. Genies, L. Rebattet and 0.Gay, personal communication, 1993. 19 Perkin-Elmer Corporation, Handbook of X-Ray Photoelectron Spectroscopy, Eden Prairie, MN, 1977. 20 E. T. Kang, K. G. Neoh, Y. L. Woo and K. L. Tan, Polym. Commun., 1991,32, 41 3. 21 D. Lin-Vien, N. B. Colthup, W. G. Fateley and J. G. Grasselli, The Handbook of Infrared and Raman Characteristic Frequencies of Organic Molecules, Academic Press, London, 1991. 22 N. S. Sariciftci, H. Kuzmany and H. Neugebauer, J. Molec. Electron., 1987,3, 141. 23 J. M. Ginder and A. J. Epstein, Phys. Rev. B, 1990,41, 10674. 24 R. M. Silverstein, G. C. Bassler and T. C. Morrill, Spectrometric Identijication of Organic Compounds, Wiley, New York, 1981. 25 D. E. Stilwell and S-M. Park, J. Electrochem. Soc., 1988,135,2491. 26 B. Wessling, Synth. Met., 1991,41-43,907. 27 J. Desilvestro and W. Scheifele, J. Muter. Chem., 1993,3, 263. 28 B. Wessling, Adu. Maters., 1993, 5, 300, and references cited therein. 29 J. Michaelson, A. J. McEvoy and T. Shimidzu, Chimia, 1993, 47,490. 30 A. Kitani, J. Yano and K. Sasaki, J. Electroanul. Chem., 1986, 209, 227. 31 C. G. Granqvist, Appl. Phys. A, 1993,57, 3. Paper 4/02015D; Received 5th April, 1994

ISSN:0959-9428    

DOI:10.1039/JM9940401775

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

J. MATER. CHEM., 1994, 4(12), 1785-1791 Preparation and Properties of stat-Copoly(oxyethylene/ 0xypropylene)-LiCIO, Polymer Electrolytes Mehdi Nekoomanesh H.,a David J. Wilson," Colin Booth*" and John R. Owenb a Manchester Polymer Centre and Department of Chemistry, University of Manchester, Manchester; UK M73 9PL Department of Chemistry, University of Southampton, Southampton, UK SO9 5NH High-molar-mass statistical copolymers of ethylene oxide and propylene oxide with compositions in the range 60-90 mol% oxyethylene units have been prepared, mixed with lithium perchlorate, and studied by differential, scanning calorimetry (DSC) and ac impedance spectroscopy. The observation by DSC of two glass transitions gave edidence of separation into salt-poor and salt-rich phases.A copolymer of 85 mol% oxyethylene mixed with LiCIO, at an 0:Li mole ratio of 24 :1 had a conductivity at 25 "C of OM 10-5 S cm-', i.e. lower than the room temperature conductivities recorded for comparable non-crystalline polymer electrolytes formed from some alternative high-molar-mass linear copolymers. Many polymers dissolve salts to form solutions (polymer electrolytes) which support ionic conductivity. The topic has been well reviewed.'-4 Polymers containing oxyethylene sequences in one form or another have yielded the most promising results. However, polymer electrolytes based on poly(oxyethy1ene) itself are not useful at room temperature, since crystallisation, either of polymer or of polymer-salt complex, is detrimental to conductivity.The useful solvent properties of poly(oxyethy1ene) are preserved in copolymers which contain oxyethylene sequences but which neither crys- tallise themselves nor form crystalline polymer-salt complexes at room temperature. Fortunately the crystallisation of poly- (oxyethylene) in helical conformation, whether of polymer or complex, is readily disrupted by any imperfections in the chain.5 Statistical copolymerisation of ethylene oxide with a comonomer represents a particularly simple, though not neces- sarily effi~ient,~.' way of suppressing crystallinity. The method is particularly attractive since high-molar-mass polymers are readily prepared by use of coordination catalysts.8p11 The Vandenberg catalyst' (triethylaluminium, water and acetyl- acetone) has been most frequently used in the preparation of high-molar-mass statistical copolymers for use as polymer electrolytes: e.g.copolymers of ethylene oxide with propylene oxide5,12,13 or other 1,2-epoxides. l4 Use of propylene oxide as comonomer is attractive, as it is readily and cheaply available, and poly(oxypropy1ene) itself has been much investigated as a polymer electrolyte. The disruption of the crystallisation of poly(oxyethy1ene) by incor- I I I 1 0.0 0.2 0.4 0.6 0.8 mole fraction E in feed Fig. 1 Calculated dependence of copolymer composition on feed composition in the statistical copolymerisation of ethylene 1 )xide and propylene oxide (rp=0.19, rE =2.4). The dashed curve is for il random copolymerisation, for which copolymer composition equals feed composition.stepwise addition of monomers to the living chain,' the result of composition drift is the formation of copolymcrs with oxyethylene content (E content) decreasing with distance along the chain from the initiator unit. For example, given the reactivity ratios listed above and an initial feed composi- tion (mole fraction ethylene oxide) xEo=0.55, cop01 ymer of composition (mole fraction E units) xE=0.78 is formed in the conversion interval 0-1 YO,but of composition xE=0.06 in the conversionporation of oxypropylene co-units is well e~tablished,~,'~,'~"~ and it is known that stat-copoly(oxyethylene/oxypropylene) with 30-40 mol% or more of oxypropylene (P) units is essentially non-crystalline at room temperature.In the present study, the Vandenberg catalyst' was used to prepare high-molar-mass copolymers. Reactivity ratios in the copolymerisation of ethylene oxide and propylene oxide (here denoted rEO and rpo) have been reported for a number of anionic and coordination catalyst system^.^^'^^" The value of rEOgenerally exceeds that of rpo by a factor of 10 or so: e.g. for equimolar triethylaluminium and water," rEO =2.4, rpo = 0.19. The present copolymerisations were generally taken to high conversion (ca. 90%) and the difference in reactivity of the two monomers was a source of composition drift. The magnitude of the drift can be judged by the plot of instan- taneous copolymer composition us.feed composition shown in Fig. 1. Given that the copolymerisation reaction involves interval 89-90%. The average composition of the copolymer recovered at 90% conversion is xE=0.61. The variation of composition along the chain is disadvantageous for suppression of crystallinity, but high conversion IS neces-sary for preparation of high-molar-mass copolymer. Since statistical copolymers used5,12-15 in polymer electrolytes have usually been prepared to high conversion, the problem of composition drift is a general one. Possible effects on the properties of the copolymers and their mixtures with LiC104 will be discussed below. Experimental Copolymers Diethyl ether (BDH, >99.5%) was refluxed with sodium wire and benzophenone for 2-3 h then distilled under nitrogen: bp 34-36 "C.Toluene (BDH, 99.5%) was similarly treated (bp J. MATER. CHEM., 1994, VOL..4 108-109 "C) and collected over type 4A molecular sieve. Acetylacetone (BDH, >98%) and triethylaluminium (Aldrich, 1.0mol dm-3 solution in hexane) were used as received. Prior to copolymerisation ethylene oxide (EO) (Fluka, >99.8%) was dried over calcium hydride for 1-2 days at 0°C and propylene oxide (PO)(BDH, >99.5YO)was dried over ground potassium hydroxide overnight at room temperature (rt). The initiator was triethylaluminium-acetylacetone-water in molar ratio 1.0 :0.5 :0.5. Triethylaluminium solution (7.8 cm3, 7.8 x lo-, mol AlEt,) was transferred under dry nitrogen to a 100cm3 three-necked flask by syringe, followed by dry diethyl ether (8 cm').The flask was placed in an ice-water bath and distilled water (70.2 mm3, 3.9 x lop3mol) was added slowly. After 0.5 h, acetylacetone (0.4 cm3, 3.9 x lop3 mol) was added and the resulting yellow solution was stirred for 16 h under nitrogen in the dark before use. Statistical copolymers were prepared from feeds of ethylene oxide with initial mole fractions in the range xE0~0.55-0.85. Copolymerisation took place in small reaction flasks sealed under vacuum by Teflon taps. The following procedure for the copolymerisation of a feed with xEo~0.55is typical. Dry toluene (40 cm3), EO (1.7 cm3, 1.52 g, 0.0346 mol) and PO (1.95 cm3, 1.67 g, 0.0288 mol) were distilled into the reaction flask, followed by injection of initiator solution (1.8 mmol of Al).The mixture was stirred at rt for 15 h. The resulting viscous mass was diluted by dichloromethane (200 cm3) before rotary evaporating it at 40°C to obtain a rubbery product, which was further dried under high vacuum for 24 h. The copolymer produced contained ca. 4 wt.% aluminium by microanalysis. Much of this was removed by equilibrating a dilute aqueous solution of the copolymer (2.5 g dm-3, 200 cm3) with Amberlite Resin IR-l20(H) (BDH, 20 g) under nitrogen. After filtration, the mixture was extracted with dichloromethane (3 x 100 cm3) and the copolymer recovered by rotary evaporation under reduced pressure at 30 "C. The resulting copolymer contained 0.3 wt. % Al. Further reduction of the aluminium content was not attempted.Details of the six samples prepared in this way are listed in Table 1: the notation adopted reflects the mol% of oxyethylene (E) units in the chains as found by NMR spectroscopy (see below). The molar masses of the samples were investigated by gel- permeation chromatography (GPC). The system comprised three PL-gel columns (each 0.75 cm id and 30 cm long) with porosities in the range 50-10' A,giving a wide range of resolution. The eluent was N,N-dimethylacetamide at 70 "C at a flow rate of 1 cm3 min-'. Solutions of samples (0.2 g drn-,) were injected through a 100 mm3 loop. Detection was by differential refractometry (Waters Model 410). The system was calibrated with poly(oxyethy1ene) standards.Molar mass distributions were wide (M,/M, >2) typical of coordination polymerisation. Molar masses 'as if poly(oxyethy1ene)' corre- sponding to the peaks of the GPC curve (Mpk)are listed in Table 1. All lay within the range Mp,=(3.5-5.5) x 10' g mol-'. Compositions were determined by I3C NMR spectroscopy. Spectra of copolymer samples dissolved in CDC13 were recorded using a Bruker AC-300 spectrometer operating at 75.5 MHz. Intensities of resonances assigned18 to backbone carbons (6, =68-71 and 72.5-75.5 for oxyethylene and oxy- propylene, respectively) served to define the overall composi- tions listed in Table 1, which were checked against the intensities of resonance of the methyl carbons (6,= 16-18). Resonances at 6,=72.64 and 73.11 assigned" to racemic and meso-PP diads were observed in the spectra of samples EP64 and EP65, with P contents greater than 30 mol%.Otherwise, within the limits of detection by our technique, P units were effectively separated by E sequences. In Table 1 it is shown that the compositions found by NMR are in satisfactory agreement with those expected for 90% conversion on the basis of the reactivity ratios. The ranges of compositions expected within each sample are also shown and it can be seen that only samples EP90 and EP85 can be regarded as even approximately homogeneous. Sample EP85 was not investigated by NMR and its composition was calculated, as indicated in Table 1. Copolymer -Sal t Mixtures Copolymer-salt mixtures were prepared by dissolving vacuum-dried copolymer (ca.0.1 g) and the required quantity of dry LiClO, in dry acetonitrile (ca. 5 cm3) under dry argon. Compositions were prepared for 0:Li =12, 18, 24 or 30, where 0:Li is the mole ratio of chain units (oxyethylene and oxypropylene) to LiClO,, which correspond to molalities in the range m=0.7 to 1.8 mol (kg polymer)-'. After shaking (1 h) the solution was transferred to a Teflon plate and the solvent evaporated under a dry argon flow, followed by mild heating under vacuum (40 "C, <0.01 mmHg, 24 h). Thermal Analysis Thermal analysis was by DSC by Perkin-Elmer DSC-7 (University of Lancaster) for the copolymers and by Perkin- Elmer DSC-4 for the polymer electrolytes. Melting T,, and glass transition q,temperatures were obtained from the DSC curves as the temperatures at the peaks and the mid-points, respectively.Enthalpies of fusion, A,,H, were obtained from peak areas. The temperature and power scales of the calor- imeters were calibrated by melting indium, and the tempera- ture calibration was checked by melting point standards. Under the conditions of use, the thermal lag of the DSC-4 was found to be about 2 K at a heating rate of 10 K min-'. Melting and glass-transition temperatures were corrected Table 1 stat-Copoly(oxyethylene/oxypropylene)s copolymer composition, xEa calculated feed calculated instantaneous composition, observed average (0-90% sample xEO EP64 0.55 EP65 0.60 EP72 0.70 EP79 0.75 EP85 0.80 EP90 0.85 xEk0.02 (estimated).M,, averagec (90% conversion) conversion) M,,/i05 g mol-' 0.64 0.61 0.78-0.06 5.4 0.65 0.66 0.81-0.15 4.5 0.72 0.76 0.86-0.42 4.6 0.79 0.81 0.89-0.54 4.0 -~ 0.85 0.91-0.65 3.7 0.90 0.89 0.93-0.75 4.5 + 10% (estimated). From NMR. J. MATER. CHEM., 1994, VOL. 4 accordingly. A similar thermal lag was assumed for the DSC-7. Experimental uncertainties were established by replicate measurements. 'As-prepared' samples of the copolymers (5-10 mg,k0.005 mg) were dried under vacuum (<0.0 1 mmHg, 25 "C, >12 h) before being sealed into aluminium pans in a dry box. These samples were cooled in the calorimeter to 0 "C and then heated at 10 K min-' to ca.80°C in order to detect the melting transition. The molten samples were then cooled at -1'0 K min-' to -100"C and the experiment repeated. Samples were also quenched (-320 K min-') from 20-30 K above their melting temperature to -100 "C, and re-heated at 10 K min-' to 80°C. Dry samples of the copolymer-salt mixtures (5-10 mg, &0.005 mg) were sealed into aluminium pans under dry conditions as described above. These samples were cooled in the calorimeter to -100"C and then heated at 10 K min-' either to ca. 80°C or, for certain samples, to 150°C. The molten samples were then quenched (-320K min-l) to -100"C and reheated. Conductivity Conductivities of the copolymer-salt mixtures were deter- mined over a range of temperatures by means of a Hewlett- Packard 4192A impedance analyser, operated over the range 5 Hz to 13 MHz. The resistance of an electrolyte was obtained as the point where semicircle and the extrapolation of the inclined spur cut the real impedance axis.A dry polymer- electrolyte film, prepared as described above, was sandwiched between two gold-plated blocking electrodes and held in place by springs within the measuring cell. This operation took place under a dry argon atmosphere with a slight positive pressure of argon maintained within the cell. The assembled cell was placed in a temperature-controlled oven (& 1 K) and conductivities were determined at several temperatures in the range 20-90°C, either on heating from 20°C or on cooling from 90°C.About 30 min was allowed for thermal equili- bration at each temperature. Film thickness was monitored at all times by means of a travelling microscope (+O.OOl cm). The reliability of the conductivities was checked by repetitive measurements of the same preparation (&2%)and of different preparations (k10%).Readings taken on heating and cooling showed no significant differences. Results and Discussion Thermal Properties Examples of DSC curves found for the copolymers themselves are shown in Fig. 2 and 3, and a summary of the results is given in Table 2. The DSC curves of all 'as-prepared' samples had multi-peaked endotherms in the temperature range 30-50 "C (e.g.Fig. 2). The enthalpies of fusion were small and consistent with extents of crystallinity in the range 1-20%, 1787 r I I I I I 20 40 60 TIT Fig.2 DSC curves obtained for as-prepared copolymers EP72 and EP85.The curves were obtained at a heating rate of 10 K min-l and are presented without correction for thermal lag. Ordinate scales and baseline slopes are arbitrary. r vEP7*t--50 0 50 TI'C Fig. 3 DSC curves obtained for copolymers EP72 and EP85 quenched from the melt. The curves were obtained at a heating rate of 10 K min-' and are presented without correction for thermal lag. Ordinate scales and baseline slopes are arbitrary. compared with fully crystalline p~ly(oxyethylene),'~ A,,H25210 J g-'. Besides evident glass transitions, the DSC curves of quenched samples EP72 to EP90 (e.g.Fig. 3) con-tained broad endothermic melting peaks at temperatures towards the bottom of the melting ranges found for 'as- prepared' samples. Melting peaks were not detected in the DSC curves of quenched samples EP65 and EP64, which is in agreement with the conclusions of other group^."^'^ The DSC curves of cooled samples (-10 K min-') were similar to those of quenched samples. The expected increase in Tp with increase in E content was obscured by experimental uncertain ties. Multiple melting of the as-prepared samples is attributable, at least in part, to non-uniform composition along the lengths of the copolymer chains. Similar effects have been observed Table 2 Thermal properties of stat-copoly(oxyethylene/oxypropylene)s copolymer T,/"c" (quenched) melting range/"C (quenched) melting range/"C (as prepared) AfusHIJ g-'(as prepared) EP64 -69 24-48 2 EP65 -73 - 27-46 2 EP72 -72 10-40 26-55 16 EP79 -70 10-46 30-56 11 EP85 -73 8-53 30-57 22 EP90 -65 5-55 30-58 38 a <k3 K (estimated).A& & 5 J g-' (estimated). in related systems: e.g. partially isotactic poly(oxypropylene).20 Evidence of cold crystallisation is difficult to pick out in Fig. 3 and is a consequence of its spread over a wide temperature range, much as expected for statistical copolymers with wide distributions of crystallisable sequence lengths.'l The effect of annealing quenched sample EP90 was investi- gated. The DSC curve of the quenched copolymer contained a small melting peak with maximum at T, =37 "C.Annealing at 35°C for 1h, followed by quenching in the DSC, resulted in a melting peak with a maximum at 42°C. Annealing this sample at 40°C for 0.5 h resulted in a further increase in the melting maximum to 48°C. After each step, the area of the melting peak had reduced, indicating a process of fractionation rather than crystal perfecting, which was a consequence of the wide composition distribution. All the copolymers were mixed with LiCIO, at a mole ratio 0:Li of 24: 1. These samples are denoted EP64-24 etc. Examples of DSC curves obtained for as-prepared samples are shown in Fig. 4. The curves obtained for samples EP64-24 to EP79-24 clearly showed two low-temperature transitions, which are assigned to distinct two glass transitions, denoted 19 EP65-24 -50 0 50 T/"C Fig.4 DSC curves obtained for copolymers EP65, EP79 and EP90 mixed with LiClO, (0:Li =24, m =0.85-0.92 mol kg- ').The curves were obtained at a heating rate of lOK mind' and are presented without correction for thermal lag. Ordinate scales and baseline slopes are arbitrary. J. MATER. CHEM., 1994, VOL. 4 Tgl and Tg2.The lower transition at Tgl was barely detectable in the DSC curve of as-prepared sample EP90-24 (see Fig. 4), but was more apparent in the DSC curve of a quenched sample (not shown). Melting peaks attributable to crystalline polymer were observed in the DSC curves of samples EP72-24 to EP90-24, but corresponding curves recorded for quenched samples showed no melting peaks.Values of Gl and Tg2,the melting range, and Afu,H are listed in Table 3. For all samples, Tgl was approximately constant at -7O"C, while values of T2were in the range -47 to -37 "C, depending on composition. Melting peaks in the temperature range 25-45°C were similar to those found for the copolymers alone. Copolymer EP85 was mixed with salt at four concentrations in the range 0:Li= 12-30, see Table 4. Crystallisation of as-prepared samples was largely suppressed at the highest salt concentration (0:Li =12). Two glass transitions were observed for samples EP85-30 and EP85-24. However, the DSC signal at the lower glass transition (GIz -70 "C) was markedly reduced as salt concentration was increased/and the transition was not observed with certainty for samples EP85-18 and EP85-12.As salt concentration was increased, the DSC signal at the higher glass transition increased, as did the value of q2itself. Two glass transitions in mixtures of poly(oxypropy1ene) and LiClO, in the concentration range 0 :Li= 11-20 have .~~been reported by Vachon et ~1 The two transitions are attributable to dilute (Tgl) and concentrated (Tg2) salt solu- tions, the dilute phase having a glass-transition temperature essentially the same as that of the parent copolymer, and the concentrated phase having its glass-transition temperature (Tg2) raised by the increased cohesion in the salt-copolymer mixture. The optical clarity of the copolymer-salt mixtures suggests microphase separation.22 Presumably, the effect in poly(oxypropy1ene) is a consequence of the low solubility of the salt compared with that in poly(oxyethy1ene).The effect in the present copolymers must also reflect a low solubility, which may well be accentuated by the wide composition distributions. ' The increase in Tp2 with increase in salt concentration is as expected. The effect of salt concentration on Tghas been much discussed in the literat~re.'-~*~~~~~ Because of the complication Table 3 Thermal properties of copolymer-LiCIO, mixtures: O= Li =24 LiClO,/ TgllCCacopolymer mol kg -' (quenched) EP64-24 0.85 -EP65-24 0.85 -71 EP72-24 0.87 -69 EP79-24 0.89 -EP85-24 0.90 -EP90-24 0.92 -" Tk 3 K (estimated). Afu,H& 5 J g-' copolymer LiC10,(0:Li) LiClO,/mol kg-' EP85 12 1.81 EP85 18 1.21 EP85 24 0.90 EP85 30 0.72 "T+3 K (estimated). AfusHt5 J g-' (estimated).T,2/K"(quenched) melting range/"C (as prepared) AfUSHlJ g-'(as prepared) 70 -37 - - -37 - - -45 30-50 10 70 -42 30-55 12 70 -47 25-55 20 71 -46 20-55 28 mixturesThermal properties of EP85-LiC10,Table 4 T,I/"C" T,,/K"(quenched) (quenched) melting range/"C (as prepared) AfusHIJ g -(as prepared) --23 -30 3 --35 20-55 15 -70 -47 25-55 20 -70 -48 35-55 16 Transition at Tgl uncertain. J. MATER. CHEM., 1994, VOL. 4 of phase separation, the present results do not add to our understanding of this aspect of polymer electrolyte chemistry.Conductivities The observation of two glass transitions, indicative of phase separation, pertains directly to low temperatures: T< -20 “C. However, solubilities of salts in poly(oxyethylene), poly(oxy- propylene) and their copolymers are known to have negative temperature coefficients,26327 as would be expected if strong solute-solvent interactions lead to a negative enthalpy of solution. Consequently detection of liquid-liquid phase separ- ation at low temperatures implies similar phase separation at high temperatures. Moreover the polymer electrolytes may be partly crystalline at temperatures below 50 “C. This compli- cated phase behaviour is not obviously reflected in the tem- perature dependences of conductivity of the present systems.This is illustrated in Fig. 5, in which the conductivities of copolymer EP85 mixed with LiC104 at three concentrations are plotted as log CJ us. T-l. These Arrhenius plots are curved, as is usual for polymer electrolytes. As illustrated in Fig. 6, linear plots were obtained by use of the Vogel-Tammann-Fulcher equation” with suitably chosen reference temperatures. The VTF equation is: CJ =o0 exp [-B/(T-To)] 2.8 3.0 3.2 3.4 lo3 WT Fig. 5 Arrhenius plot. Logarithm of conductivity (0)us. reciprocal temperature for copolymer EP85 mixed with LiClO, in the 0:Li mole ratios, of 12 (O), 18 (a)and 24 (A).The results (not shown) for 0:Li =30 overlap those for 0 :Li =24. r I I I I I 6 8 10 12 14 103 W(T-T~) 1789 where go=A/T”’, and A and B are parameters, assumed to be independent of temperature, reflecting the number of charge carriers and the apparent activation energy for segmental motion, respectively.According to the VTF cquation, assuming that parameter B is independent of salt concen-tration, the local viscosity is determined by the difference between the temperature of measurement and Tg. Plots based on T,= q2-20 gave adequate straight lines: e.g. Fig. 6. These and similar plots were interpolated to obtain isothermal conductivities at 298 or 330 K and isoviscous conductivities (i.e. conductivities adjusted to a constant value of T-T,) at q2+ 105 K, the latter corresponding to temperatures (330-355 K) above the melting range of the copolymer-salt mixtures.In carrying through the calculations in this way it was assumed that the conductivity in these systems was effected predominantly through the concentrated-sal t phase. In fact, the variation of q2with overall salt concentration found in the present work was similar to that found2’ for non-crystalline, single-phase, oxymethylene-linked-poly(oxy-ethylene)-LiClO, electrolytes, which lends support to this assumption. The effect of salt concentration on the Conductivities of EP85 electrolytes is shown in Fig. 7. As salt molality was increased beyond 1 mol kg- ’, the isothermal conductivity (330 K, 57°C) fell from a maximum value of cu. 1.5 x S cm-’, see Fig. 7(u).This fall at high salt concen- tration can be ascribed to an increase in local vis~osity.~~’~,~~~~~ Isoviscous conductivities increased regularly with salt concen- tration, see Fig.7(b).The straight line drawn in Fig. 7(b)has a slope of unity, consistent with a one-to-one correspondence between isoviscous conductivity and salt concentralion, as found for other polymer-electrolyte sy~tem~.~~~~~~~~~~ The effect of copolymer composition on conductivity is shown in Fig. 8. The results are for salt concentration 0 :Li = -0.2 0.0 0.2 -3.5:-4.0 IfI I I 1 Fig.6 VTF plot. Logarithm of T1’20 cs. l/(T-To) for copolymer EP85 mixed with LiC10, in mole ratio 0:Li at mole ratios of 12 (O), 18 (m)and 24 (A),The reference temperature Tois taken to be T,,-20, where Tg2is the temperature at the higher of the two glass transitions. The results (not shown) for 0:Li= 30 overlap those for 0:Li= 24.Fig. 7 (a) Logarithm of isothermal conductivity PS. log (salt rnolality) for copolymer PE85 mixed with LiClO,: T= 330 K. (b) Logarithm of isoviscous conductivity us. log (salt molality) for copolymer PE85 mixed with LiClO,: T= Tg+ 105 K; slope = 1. 0-4c 0 0.6 0.7 0.8 0.9 XE Fig. 8 Logarithm of conductivity us. mole fraction oxyethylene units (xF) for PE copolymers mixed with LiClO, (O:Li=24, mz0.9 mol kg-I): 0, T=330K (57°C); B,T=298 K (25°C) 24 (rnz0.9 mol kg-') and for temperatures T= 330 K (57 "C) and T=298 (25 'C). It is clear that conductivities were generally reduced by reducing the oxyethylene content of the copolymer.The trend in G2(Table 3) is towards higher values as xE is reduced, which is in keeping with the conductivity results. At the lower temperature there is an indication (but not outside our experimental error) of a maximum in conduc- tivity at ca. 80 mol% E, somewhat as found by Florjanczyk et al. for EP copolymer-NaI electrolytes.12 As a result of crystallinity, the conductivities of poly(oxyethy1ene)-based electrolytes are very low at, or about, room temperature, so a maximum in conductivity as the E-content approaches 100 mol% is expected. Comparison with Other Polymer Hosts Compared with other n on-crys talline, poly (ox yet hy1ene)- based polymer hosts, which are good solvents for LiClO,, the levels of maximum conductivity in the EP copolymer systems are significantly lower.Approximate maximum conductivities are set out in Table 5. There is a clear advantage in using a modified poly(oxyethy1ene) rather than an EP copolymer. In this respect, copolymer ED70 (Table 5) is essentially a modi- fied poly(oxyethylene), since the side chain contains two oxyethylene units: -CH2(OCH2CH2),CH3. The advantage of POMOE400 over copolymer ED70 lies in a more efficient suppression of ~rystallinity.~,~ Comparison with Low-molar-mass stat-Copoly (oxyethylene/oxypropylene) Cameron et al. have reported thermal and electrochemical properties for polymer electrolytes based on liquid stat-copoly (oxyethylene/oxypropylene)s: e.g. M, in the range 1700-33OOg mol-l, 50 or 75 wt.% E.27,30.31The concen-Table 5 Approximate maximum conductivities for non-crystalline PO-based polymer hosts T' C EP85" /to5 S cm-' ED70h/ lo5 S cm-' POM0E40Oc/ lo5 S cm-' 57 10 10 40 20 1 2 3 LiClO, plus copolymer EP85, Mp,(GPC)%4x lo5 g mol-' (present work); 'LiCF,SO, plus statistical copolymers of ethylene oxide and digol methyl glycidyl ether, M,,.(GPC)% 1 x lo6 g mol-';14 LiCIO, plus oxymet hylene-linked poly(oxyethy1ene) prepared from PEG400, Mpk(GPC)% 1.4 x lo5 g mol-'.25 J. MATER.CHEM., 1994, VOL. 4 tration dependence of molar conductivity established in their work has served as a guide to conductivities in other non- crystalline polymer-electrolyte system^.^^'^^ So far as the pre- sent study is concerned, the bFneficia1 effect on conductivity of a high oxyethylene content, seen in the present results (Fig.8), is equally seen in the results for liquid system^.^^.^' Cry stallisation and melting occurred at substantially lower temperatures than found for the present high-molar-mass samples: e.g. melting from -30 to +2O"C for a liquid copolymer with 80 mol% E (75 wt.% E) compared with +30 to +55 "C for sample EP79.31 Characterisation by 13C NMR of the commercial copolymers referred to in ref. 30 and 31 has shown32 that their sequence length distributions were identical to those expected in the absence of composition drift,I6 i.e. that their average E-sequence lengths were shorter than those of the present copolymers. This characteristic, coupled with the effect of chain ends, makes close comparison of results from the two systems difficult.Just one glass-transition temperature was found3' for mixtures of liquid copolymer (80 mol% E) with lithium perchlorate, which may be a consequence of the difference in sequence length distri- bution, but equally of the better miscibility expected in a low- molar-mass system. Concluding Remarks The present study touches on a number of aspects of the chemistry of polymer electrolytes based on high-molar-mass statistical copoly(oxyethylene/oxypropylene)s. Separation into salt-poor and salt-rich phases, similar to that found for poly(oxypropy1ene)-LiC104 electrolytes,22 was identified via DSC. This phase separation was most easily detected in electrolytes of low salt content formed from copolymers of low E content. Presumably, the conductivities of these electro- lytes were limited by this solubility effect.At the other extreme of high E content, 'room temperature' conductivity was limited by crystallisation. A maximum conductivity at 25 'C of G% lo-' S cm-' was found for a copolymer with E content = 85 mol% mixed with LiC10, at a 0:Li mole ratio of 24: 1. For that copolymer, EP85, the extent of phase separation was small, and both the glass-transition temperature assigned to the salt-rich phase (q2)and the conductivity depended on overall salt concentration in a manner consistent with results for comparable single-phase systems.21 Thanks are due to the Iranian Government and the Science and Engineering Research Council for financial help.Drs. C. V. Nicholas, F. Heatley, J. H. Thatcher and G. E. Yu gave valuable advice, and Mr. K. Nixon and Mr. M. Hart gave practical help. Dr. J. Ebdon kindly made arrangements for use of equipment at Lancaster University. Our referee drew attention to ref. 31, which appeared just as our paper was submitted, and suggested inclusion of a comment in our discussion. References Polymer Electrolyte Reviews ed. J. R. MacCallum and C. A. Vincent, Elsevier, London, 1987, Vol. I; 1989. vol. 2. J. R. Owen, in Covlzprehensior Poljwier Science, ed. C. Booth and C. Price, Pergamon Press, Oxford, 1989, vol. 2. ch. 21. F. M. Gray, Solid Polymer Electrolytes, VCH, Cambridge, 1991.P. G. Bruce and C. A. Vincent, J. Clzem. SOL..,Furudnj) Truns., 1993,89,3187. C. Booth, C. V. Nicholas and D. J. Wilson, Polymer Electrolytc~ Reviews, ed. J. R. MacCallum and C. A. Vincent, Elsevier. London, 1989, vol. 2, ch. 7. B-X. Liao, Y-M. Chen, C. Booth and Y-Z. Luo. Polym. Commun., 1991,32, 348. J. MATER. CHEM., 1994, VOL. 4 7 8 9 10 11 12 13 14 15 16 17 18 19 20 J. H. Thatcher, K. Thanapprapasr, S. Nagae, S-M. Mai, C. Booth and J. R. Owen, J. Muter. Chem., 1994,4,591. F. E. Bailey and H. G. France, J. Polym. Sci., 1960, 45,243. E. J. Vandenberg, J. Polym. Sci., Part Al, Polym. Chem., 1969, 7, 525. Ph. Teyssie, T. Ouhadi and J. P. Bioul, International Review of Science, Macromolecular Science, Physical Chemistry, ed.C. E. H. Bawn, Butterworths, London, 1975, series 2, vol. 8, p. 191. C. Booth, W. C. E. Higginson and E. Powell, Polymer, 1964, 5,479. Z. Florjanczyk, W. Krawiec, W. Wieczorek and J. Przyluski, Angew. Mukromol. Chem., 1991,187, 19. J. Przyluski and W. Wieczorek, Solid State Ionics, 1992, 53-56, 1071. D. G. H. Ballard, P. Cheshire, T. S. Mann and J. E. Przeworski, Mmromolecules, 1990, 23, 1256. P. Passiniemi, S. Takkumaki, J. Kankare, M. Syrjama, Solid State lonics, 1987,28-30, 1001. F. Heatley, G-E. Yu, C. Booth and T. G. Blease, Eur. Polym. J., 1991.27, 573. T. N. Kurengina, L. V. Alferova and V. A. Kroprachev, Vysokomol. Soedin., Ser. B, 1971, 13, 419: Chem. Abstr., 1972, 75,118631h.F. Heatley, Y-2. Luo, J-F. Ding, R. H. Mobbs and C. Booth, Macromolecules, 1988,21,2713. D. R. Beech and C. Booth, J. Polym. Sci., Part B, Polym. Phys., 1970,8, 731. C. Booth, C. J. Devoy, D. V. Dodgson and I. H. Hillier, J. Polym. Sci., Part A2, Polym. Chem., 1970,8, 519. 21 L. Mandelkern, Crystallisation of Polymers, McGraw -Hill, New York, 1964, ch. 8. 22 C. Vachon, M. Vasco, M. Perrier and J. Prud’homme, Macromolecules, 1993,26,4023. 23 J-F. LeNest, A. Gandini and H. Cheradame, Br. Polyw. J., 1988, 20, 253; H. Cheredame and J-F. LeNest, Polymer Electrolyte Reviews, ed. J. R. MacCallum and C. A. Vincent, Elsevier, London, 1987, vol. 1, ch. 5. 24 J. M. G. Cowie and A. C. S. Martin, Polymer, 1991,32,2411. 25 S. Nagae, M. Nekoomanesh H., C. Booth and J. R. Owen, Solid State lonics, 1992,53-56, 1118. 26 D. Teeters and R. Frech, Solid State Ionics, 1986, 18-19.271. 27 G. C. Cameron and M. D. Ingram, Polymer Electrolyte Reviews ed. J. R. MacCallum and C. A. Vincent, Elsevier, London, 1989, vol. 2, ch. 5. 28 H. Vogel, Phys. Z., 1921, 22, 645; G. Tammann and W. Hesse, 2.Anorg. Allg. Chem., 1926,156,245; G. S. Fulcher, J. Am. Cerum. SOC.,1925,8, 339. 29 M. Nekoomanesh H., S. Nagae, C. Booth and J. R. Owen, J. Electrochem. Soc., 1992,139, 3046. 30 G. C. Cameron, M. D. Ingram and G. A. Sorrie, J. Chem. SOC., Faraday Trans. I, 1987,83,3345. 31 G. C. Cameron, M. D. Ingham, M. Y. Qureshi, G. M. Russel and G. I. Wood, Polym. Znt., 1994,33, 347. 32 F. Heatley, personal communication. Paper 4/03157A; Received 26th hluy, 1994

ISSN:0959-9428    

DOI:10.1039/JM9940401785

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

J. MATER. CHEM., 1994, 4( 12), 1793-1797 Comparative Kinetic Analyses for Epoxy Resins cured with Imidazole-Metal Complexes Gabriel J. Buist,a Ian Hamerton,*a Brendan J. Howlin," John R. Jones," Shuyuan Liu" and John M. Bartonb aDepartment of Chemistry, University of Surrey, Guildford, Surrey, UK GU2 5XH b Structural Materials Centre, Non-metallics, Defence Research Agency, Farnborough, Hampshire, UK GU74 6TD Proton nuclear magnetic resonance ('H NMR) spectroscopy experiments were carried out for a commercial epoxy resin system in [2H6]DMS0 solution and in bulk. Good agreement was obtained between the secondary rate constants found for the epoxide polyetherification reaction when monitored by Fourier-transform infrared (FTIR) or 'H NMR spectroscopy in the bulk over the range of temperatures studied.This highlights the usefulness of the high temperature bulk NMR technique in kinetic studies of polymerization. Epoxy resins are an extremely versatile family of thermosetting polymers and a wide variety of curing agents may be used in their processing.' The use of imidazoles as curing agents is well and they are known to produce cured products with good physico-mechanical properties. Further- more, at elevated temperatures they exhibit a fast catalytic action upon the process of epoxide homopolymerization (polyetherification), which occurs through the opening of the oxirane ring (Fig. 1). Imidazoles are known to display poor storage stability and, in the past, work has been directed at overcoming this pr~blem.~ Elsewhere we have the use of copper complexes of the adducts of phenyl glycidyl ether (PGE)and 2-ethyl-4-methylimidazole (EMI) (designated 1 and 2, respectively in Fig.1) as curing agents for epoxy resins, which display improved solubility and storage stability enabling their formulation in one-pot compositions. Whilst remaining stable at ambient and low temperature, the complex r 1 dissociates at ca. 120°C to produce the adduct 4. The imidazole-induced cure reaction is depicted in €ig. 2. It involves two consecutive reactions: (i) the activation of the lone pair of electrons on the imidazole ring to atrack the oxirane ring, resulting in the opening of the epoxy group (kl); and (ii) the base (alkoxide) catalysed homopolymerization of the epoxy ring (polyetherification) and subsequent network formation, a first-order reaction under the experimental con- ditions (k2).The properties of cured epoxy resins are very much dependent on the chemical structure and extent of crosslinking within the resin network, hence it is necessary to have a full understanding of the processes of resin network formation. To date many traditional methods have been used to study epoxy cure mechanisms including FTIR' and differential scanning calorimetry (DSC),9 although little work has been carried out into the kinetic aspects of the curing reaction of epoxies catalysed in this manner.Jones el ~1."~" CUCI,1 YN:eO-CH2-CH-CH2-N CH2I CH3 4 1 r 1 /\c b ?H0dHZC-CH-CHZ-0 \ / \ 0-CH2-CH-CH2-0 CH3 CH3ardn 3 Fig.1 Structures of the compounds employed in this study (with 'H NMR designations) J. MATER. CHEM.. 1994, VOL. 4 C?H dCH3T = 120°C ~O-CH,-CH-CH,-N /=(YH 00-CH, -CH-CH,--N CUCI;! -CH, CH,II CH3CH3 -4 41 oligomer formation 4 + epoxy 3 ring-opened intermediate 5 0-YH-y2 YACH3-7 p, ACH3 -NyN;CHp-CH-y CH2-CH-k2 * N CH2-CH--NYFd' c' CHZ CH2 I I CH3 CH3 polyetherif icat ion 5 + epoxy 3 and network formation Fig. 2 Proposed mechanism of epoxy cure involving the metal-imidazole complexes developed a radiochemical tracer method for the study of epoxide cure kinetics that gives accurate, quantitative infor- mation about the reactants, intermediates and products. Bouillon et all2 studied polymerization mechanisms of PGE cured with BF, complexes of aniline using gel-permeation (GPC) and high-performance liquid chromatography (HPLC).However, to date NMR spectroscopy, which is probably the most versatile of all the spectroscopic techniques, does not appear to have been introduced into this area. NMR techniques have improved dramatically in recent years and it is now possible to study complex reaction mixtures. Most dynamic NMR kinetic studies are based on equilibrium systems. However, for an irreversible reaction, it is possible to monitor the reaction quantitatively using the chemical shifts of the reactants, intermediates and products, which can be resolved by integration of the NMR signals as a function of time.The reaction chosen here is that between the copper(I1) complexes of the adduct of PGE and EM1 1 and 2 and a commercial prepolymer of bisphenol-A diglycidyl ether (3). Experimental Equipment 'H NMR spectra were obtained both in [2H6]DMS0 and in the bulk at a range of temperatures by using a Bruker AC-300 high field FT NMR spectrometer operating at 300.13 MHz (a minimum of 64 scans were collected). A ceramic NMR tube spinner and a Bruker B-VT 1000 variable-temperature unit were used for the measurements made at elevated temperatures in the range 120-165 "C (as described elsewhere).6 The sample tube was loaded into the probe after the desired temperature had been reached and measurements made at preprogrammed time intervals using an automated routine with the spectrometer operating in the unlocked mode for bulk (solvent-free) samples and the free-induction decay (FID) signals saved.The ratio of the integrals of the epoxide methylene protons (the doublet at 6 x1.56 corresponding to Hd in Fig. 1) and an internal standard, the methyl proton in the isopropylidene bridge (a singlet at 6 =0.6 corresponding to Ha), was determined and converted to epoxide concen- tration ([El). This ratio was referenced against that of the signals at the beginning of the cure of the MY750 prepolymer (3) to provide a measure of conversion during cure. where I(Hd/Ha) is the ratio of the integral of H, (epoxide) and Ha (methyl group as internal standard) signals, lois the l(Hd/Ha) value at the beginning of the cure and x is the fractional conversion of the epoxide.IR spectra were recorded using a Perkin-Elmer 1750 FT-IR spectrometer interfaced with a Perkin-Elmer 7300 computer; the samples were presented as thin films (ca. 0.025 mm) on KBr plates in a thermostated cell holder. FTIR measurements were made at preprogrammed time intervals using an auto- mated routine with the spectrometer (samples were scanned 24 times at a resolution of 2cm-'). The ratio of the peak heights (in absorbance) of the epoxide ring stretch (914 cm-') and the C-C aromatic ring stretch (1605 cm-' ') as an internal standard, was calculated and converted to epoxide ring con- centration as follows: where A914/1605 is the ratio of the absorbances at 914 cm-I (epoxide) and 1605 cm-' (aromatic ring as internal standard), A, is the A914/1605 value after full curing (assume the conver- J.MATER. CHEM., 1994, VOL. 4 sion is 100% at this stage) and A, is the A914/1605 value at the beginning of the cure. Materials The commercial epoxy prepolymer MY750 (Fig. 1, 3) was provided by Ciba-Geigy. PGE and EM1 were obtained from Aldrich Chemical Co. and purities were determined using 'H NMR. Copper(I1) chloride (Aldrich) gave satisfactory analyt- ical results. The preparation of the 1 : 1 adduct of PGE and EM1 ( PGE-EMI) (4) and the corresponding copper complex, Cu(PGE-EMI),CI, (1), have already been reported else-where' as have the corresponding 2: 1 adduct (PGE,-EMI) and its complex Cu(PGE-EMI2),CI2 (2). The adducts were dispersed directly in the resin, while the complexes (10 mol% in MY750) were dissolved in AnalaR acetone prior to mixing (the solvent being removed under vacuum at room tempera- ture and the resulting mixture injected into a number of 5 mm NMR tubes, these were then stored in a freezer prior to use).Results Solution 'H NMR Study At elevated temperatures (100-140 "C) the viscosity of the epoxy resins is greatly reduced resulting in a dramatic improvement in the resolution of the NMR spectra, especially for those of high concentration. The chemical shifts of the starting materials, intermediates and the products are well resolved (Fig. 3) and hence it is possible to monitor the extent of the reaction by direct integration of these signals.However, because of the limitations imposed by the sensitivity of the 'H NMR method, it is necessary to use a greater acquisition time and it becomes more appropriate to study those reactions with first-order rate constants < s-'. Fig. 3 depicts a stacked plot for the progressive cure of a sample of commercial epoxy prepolymer MY750 (3) initiated 3.5 3 2.5 2 1.5 s Fig. 3 'H NMR spectra of MY750-Cu( PGE-EMI),Cl, in [2H6]DMSO as a function of reaction time at 150"C (Hb not shown) with Cu(PGE-EMI),Cl, (13 mol%) in C2H6]DR/BS0 (as an 80% solution) at 149 "C. In this curing reaction (Fig. 2) protons H, and H, in the initial prepolymer (see dthsignations in Fig.1)are shifted to new positions (H,, and Hd,respectively) as cure proceeds; it is possible to resolve protons €I,, Hd and H,, and Ha in the spectra. Proton Ha does not participate in the reaction and so its chemical shift remains tinchanged (hence it may be used as a reference signal in a qitantitative ratio analysis). The fractional conversion of the resin at each stage of the reaction can be determined from the relative integrations of signals Hb and H, against the hiitial (0% conversion) and infinity ( 100% apparent conversion) reference spectra. Fig. 4 depicts the fractional conversion of epoxy resin referenced to Ha in this manner as a function of reaction time. The rate constant of the cure reaction was deriwd from a linear regression analysis of the logarithm of the relative integrations of Hb, H, and Hb,,respectively, as a function of time (Fig.5). From these plots it is seen that the dala deviate from linearity. This may be attributed to reduced solubility due to polymerization and crosslinking. It is inevitable that some reduction in resolution will result as the reactio 11mixture solidifies and if we neglect those unreliable data from what is effectively the solid state then the correlation coefficients are greater than 0.99. The results show that as expected this is a first-order reaction, k2=4.03 x lop5s-' (at 150 "C). Bulk 'H NMR Study In an earlier publication6 we demonstrated that for d sample containing 10 mol% of curing agent, recorded at a temperature of 163 "C over the course of 10 h, the narrow lines and good 1.OOr -tlmin Fig.4 Fractional conversion derived from ratio of H, (0)and Hd(m)from 'H NMR in ['H6] DMSO at 150"C -1.0 -h m< 5-c -2.0-h I"IE E -3.0-r (61 L 1 1-4.0-20 20 60 100 tlmin Fig. 5 First-order kinetic plot of MY750-Cu( PGE-EMI),Cl, in ['HJ DMSO at 150 "C: (a)In(HJH,), (b)In(H,/H,) -41 . I 0 130 260 390 520 650 t/min Fig. 6 Consecutive first-order plots of MY750-Cu( PCE-EMI)&l2 in (bulk 'H NMR) at 150°C: (a) ln[E], (b)ln(differences). Table 1 'H NMR kinetic data for MY750-Cu(EMI-PGE),C12 at a range of temperatures (in the absence of solvent) T/"C k,"/min -' k/ /min -' 130 0.0134 5.54 x 10-4 135 0.0168 7.68 x 10-4 140 0.0243 1.11 x 10-3 150 0.0269 1.70 x 10-3 163 0.0385 2.59 x 10-3 ~~~~~~~ ~ a k, and k2 refer to reaction steps in Fig.2. I-121 U 0.0023 0.0024 0.0025 1/T Fig. 7 Arrhenius plots of (a) the oligomer formation reaction (k,) and (b)the etherification reaction (k,) resolution make the calculation of epoxide concentration and of the extent of cure simple and straightforward. When the logarithm of the epoxide concentration is plotted against time (Fig. 6) the results appear as two consecutive first-order processes whose rates are sufficiently different so as to be able to calculate both rate constants (Table l), an important advantage of the method over the solution NMR technique (from which only k2 could be calculated). The plot for k, was obtained from the differences between the extrapolation of the linear portion of the h[E] plot and the points between t =O and 110 min.These reactions have first-order rate con- stants (k,=4.48 x s-', kZ= 1.70 x s-' at 150 "C) that are conveniently slow so that the time taken for spectrum acquisition (109 s per spectrum) does not cause a problem. A series of measurements were made at different temperatures enabling Arrhenius parameters to be obtained (Fig. 7). FTIR Kinetics FTIR spectra were recorded for a sample containing 10 mol% of curing agent at a temperature of 140°C over the course of 10h. When the logarithm of the epoxide concentration is plotted against time (Fig. 8) the results appear as two con- J.MATER. CHEM., 1994, VOL. 4 -1.2 hf -1.4 2 v< -C -1.6 -1.8 tlmin Fig.8 Consecutive first-order plots of the cure of MY750-Cu(PGE-EMI),C12 (10 mol%) at 140 "C by FTIR Table 2 Curing reaction parameters obtained from several analytical techniques monitoring curing agent kl/10-6 k,/lO-' technique T/"C (molo/o) S-' S-' 'H NMR 150 13 -4.03 (C2H61DMSO)'H NMR 140 10 4.05 1.85 (fused state) FTIR 140 10 -1.88 secutive first-order processes, but unlike high-temperature 'H NMR spectroscopy, these rates are not sufficiently resolved to be able to calculate both rate constants. The first-order rate constant for the polyetherification reaction (k2= 1.88 x lo-' s-l at 140°C) is in close agreement with that obtained using high-temperature 'H NMR spectroscopy (Table 2).Discussion Tmidazoles are added to epoxy systems to catalyse the homo- polymerization of epoxide groups (polyetherification), but unmodified imidazoles begin to react when mixed with epox- ides (cure occurs slowly at room temperature) making them unsuitable for use in one-pot compositions. Transition metals have been used to prepare complexes of imidazoles that react very slowly at room temperature, but have exhibited a rapid cure at elevated temperatures. The complexation of a trans- ition metal (in this case copper) effectively arrests the poly- etherification reaction at ambient temperature until the tem- perature is elevated to effect cure. A further advantage over existing imidazole curing agents is the efficiency of com-plexation.After a period of time at the cure temperature (e.g. 120"Cor 140"C)the epoxy-complex mixture can be quenched at room temperature with no further advancement of cure.7 This development makes the tailoring of a commercial epoxy system possible thus facilitating more complex cure schedules in a more controllable manner. At present the exact mechan- ism by which the reaction is quenched is unclear. Re-association is a distinct possibility, but it must be borne in mind that the copper plays no further part in the reaction once the cure has been initiated. Hence, the possibility of association with the alkoxide (RO-) groups formed during the reaction (Fig. 2) can not be discounted at this stage.The cure process is summarized by the following scheme: J. MATER. CHEM., 1994, VOL. 4 A4CuC1, 4A + CuC12 A+E*AE AE + ELAEE AEE+E-%AEEE AE ... E,-, + ELAE... E, where A represents the PGE-imidazole adduct (l),E rep-resents PGE and AE, AEE etc. represent successive oligomers. We assume that the dissociation occurs rapidly and plays no part in the kinetics of cure. The k, step involves imidazole- induced opening of the oxirane ring, the k, and succeeding steps involve alkoxide-induced etherification. As a first approximation we assume k, =k, =. . . k, because these steps are essentially the same, and involve oligomers of increasing chain length. On this basis the rate of loss of PGE is given by: -dCEl/d~=k1CAl~El +k,CEI"AEI +[AEE] + .. . + CAE.. .En-,I) Let CAIo represent the initial concentration of adduct, then: [A] =[A10 -(CAE] + [AEE] + . . . +CAE.. .En- 11) Hence, -d CElldt =kl CAlCEl+ k2 CEI(CAl0-CAI) In the initial stage of cure the k2 term is negligible, and d[E]/dt is equal to d[A]/dt: -d[A)/dt=k, [A][E] The epoxide is present in excess, so first-order kinetics are expected for this stage. When all of the adduct has been consumed, the k, term is negligible: -d CElldt =k2 [El CAI0 Again, first-order kinetics are expected, this time because CAIo is a constant. When ln[E] (from the NMR measurements) is plotted against time, the initial points fall on a curve, but the remainder of the plot is linear (Fig. 6). The appearance of the plot suggests that a consecutive first-order treatment is appli- cable.The linear portion was extrapolated back to the ln[E] axis, and the differences between [El calculated from the extrapolated line and [El observed were calculated. The plot of ln(differences) against time is linear (Fig. 6) showing that, to a good approximation, the treatment is justified. The rate constants were calculated from the slopes of the linear plots; the ratio k,:k, is 15 or greater (it varies with temperature), therefore it is reasonable to assume that the epoxide is present in excess throughout the first stage. Arrhenius plots for kl and k2 (Table 1 and Fig. 7) give respective activation energies of 45 and 60 kJ mol-'. Conclusions The results of this work show that 'H NMR spectroscopy is valuable for monitoring the kinetics of polymerization in 'real time', prior to gelation, of a diepoxide with a soluble organometallic catalyst.Experiments were carried out in solution in C2H6]DMS0 and in bulk. There is an advantage in monitoring the reaction in bulk as there is no precipitation of material due to non-compatibility of the polymer with the solvent. This study shows that good agreement can be found between the secondary rate constants found for the reaction when monitored by FTIR or 'H NMR spectroscopy in the bulk (Table 2). Again good agreement is found over the range of temperatures studied and this points to the usefulness of the high-temperature bulk NMR technique in kinetic studies of polymerization.The work of Shuyuan Liu was generously supported by the Structural Materials Centre, Defence Research Agency, Farnborough, Hampshire, UK. The commercial epoxy pre- polymer (MY750) was kindly donated by Mr. Ian Gurnell and Mrs. Debbie Stone of Ciba-Geigy (UK) Duxford, Cambridgeshire, UK. We are grateful to Dr. Y Sun (Robotics Centre, University of Surrey, Guildford, Surrey, UK) for help with graphics presentation. References 1 W. R. Ashcroft, in Chemistry and Technology of Epoxy Resins, ed. B Ellis, Blackie Academic and Professional, London and Glasgow, 1993, ch. 2, pp. 58-59. 2 M. Ito, H. Hata and K. Kamagata, J. Appl. Polym. Sci., 1987, 33, 1843. 3 R. J. Jackson, A. M. Pigneri and E. C. Gaigoci, SAMPE J., 1987, 23, 16. 4 J. M. Barton, Br. Pat., 2135316B, 1984. 5 J. M. Barton, G. J. Buist, I. Hamerton, B. J. Howlin, J. R. Jones and S. Liu, J. Muter. Chem., 1994,4, 379. 6 J. M. Barton, G. J. Buist, I. Hamerton, B. J. Howlin, J. R. Jones and S. Liu, Polym. Bull., 1994,33,215. 7 J. M. Barton, I. Hamerton, B. J. Howlin, J. R. Jones and S. Liu, Polym. Bull., 1994,33, 347. 8 F. Ricciardi, M. M. Jonillie, W. A. Romanchick and A. R. Griscavage, J. Polym. Sci., Polym. Lett., 1982,20, 127. 9 J. M. Barton and P. M. Shepherd, Makromol. Chem., 1975, 176, 919. 10 J. R. Jones, C. Poncipe, J. M. Barton and W. W. Wright, Br. Polym. J., 1986, 18, 312. 11 G. J. Buist, A. J. Hagger, J. R. Jones, J. M. Barton and W. W. Wright, Polym. Commun., 1988,29, 5. 12 N. Bouillon, J-P. Pascault and L. Tighzert, Makromol. Chem., 1990,191,1417. Paper 4/04276J; Received 13th July, 1994

ISSN:0959-9428    

DOI:10.1039/JM9940401793

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

J. MATER. CHEM., 1994, 4(12), 1799-1803 Polypyrrole-Poly(epich1orohydrin-co-Ethylene Oxide) Blend: An Electroactive, Electrochromic and Elastomeric Material Marco-A. De Paoli* and Daltamir J. Maia lnsfituto de Quimica, Universidade Estadual de Campinas, C. Postal 6754, 73084- 700 Campinas, SP,Brazil We report on the preparation of an elastomeric blend with electrochemical and spectroelectrochemical properties similar to those of pure polypyrrole. The title elastomer used is an ionic conductor. Cyclic voltammetry and chronoamper- ometry experiments show the electroactivity of the blend. A transmittance contrast of 50% at 700 nm between the reduced and the oxidized forms of the blend is evidence of the pronounced electrochromism of the blend. Differential scanning calorimetry suggests an association of the guest conductive polymer with the ethylene oxide blocks of the rubber copolymer host.Stress-strain measurements show that the conductive polymer guest increases the rigidity and toughness of the elastomer host. Mixtures of polymers range from homogeneous to hetero- geneous and are classified by plastic technologists as blends or composites. Perfectly homogeneous mixtures, however, are not thermodynamically stable.’ Thus, a certain degree of immiscibility often occurs. Polymeric blends of two or more polymers are obtained by mechanical mixing, solution casting or polymerization of one component in a polymeric matrix. There is a vast amount of literature on the field and the production of blends became very important in the last decade for obtaining new materials by combining well known poly- mers.2 The aim of making these mixtures is to achieve a synergistic combination of the properties of the components of the blend. With blends of conductive and insulating poly- mers, the objective is the preparation of polymeric materials with good mechanical properties and the processability associ- ated with electronic conductivity or electrochromism. Conductive blends can be prepared by mechanical mixing, casting of a solution containing the components of the blend or polymerization of one polymer into another.The last method can be achieved either chemically or electrochemically producing blends or interpenetrating networks. Besides the methods used to characterize polymeric materials, these blends can also be studied by electrochemical methods, owing to the redox characteristics of the doping process of the conductive polymer.However, for technological applications it is also important to explain the ionic diffusion and structural changes occurring during the redox process. Several researchers also use electrochemical methods alongside spectroscopic tech- niques, such as Raman, IR, UV-VIS, EPR and ellipsometry. Polypyrrole has been widely studied although its conduc- tivity is not as high as that of polyacetylene. Its stability to exposure to the environment and to repeated redox cycles, however, make it very attractive for technological appli- cation~.~Its colour ranges from a light yellow in the reduced form to a deep brown in the oxidized state.When polypyrrole is oxidized, i.e. when the pyrrole chain is positively charged, the anions of the electrolyte are drawn into the material to neutralize the charge. Electrogravimetry using a quartz crystal microbalance has shown that, depending on the hydration radius of the dopant anion, there can be diffusion of the cation or of the anion of the electrolyte into the polymer bulk.4 If the polymer is doped with inorganic low molecular weight anions, for example C104-, during reduction this anion diffuses into the electrolyte and during oxidation it is reinserted into the polymer. On the other hand, if one uses anionic surfactant dopants (dodecyl sulfate or p-toluene sul- fonate), there is no removal of the dopant during the reduction process, but insertion of a cation.During the reoxidation this cation may diffuse back into the electrolyte, or insertion of a further anion may take place, depending on the potential range used. These changes are followed by intense spectral changes. Conductive polymeric blends were first prepared by the electrochemical deposition of polypyrrole onto an electrode coated with a film of poly(viny1 chloride), PVC.’ In this method the insulating material is swollen by the electrolyte solution containing the monomer; the monomer bcgins to polymerize at the electrode/polymer interface, and the poly- merization then advances across the polymer phasc to the polymer/electrolyte interface.The combination of the elec- tronic properties of the conducting phase and the mechanical properties of the insulating phase produced a unique material with conductivities in the range 10-100 S cm-’ and thermo- plastic-like mechanical properties. Following the electrode-coating method, blends wtrre pre- pared with polypyrrole and PVC and with polypyrrlde and brominated poly(vinylcarbazo1e); the electrochromism of these samples was studied.6 An electrical conductivity of 2 S cm-’ coupled with 60% transmittance of light at 633 nm was achieved for this blend prepared by potentiostatic pyrrole polymerization onto an IT0 electrode covered with a film of the insulating host polymer. According to the authors, the bleached reduced blend is more stable than pure polypyrrole prepared under the same conditions.Using different heterocycles, such as dithieno [2,3-h: 2’,3’- d] pyrrole, 5,10,1O-trimethyl-5,1O-dihydrodibenzo[b,e] azasi-line and N-vinylcarbazole, blends with PVC were electro- chemically prepared by the electrode-coating mcthod.’ Blending with PVC was reported to ameliorate the stability of the polyheterocycles. The blends showed strong electro- chromic contrast in the visible region giving rise to potential applications in electrochromic devices. Chemical polymerization was also used for the preparation of polypyrrole-PVC blends by the interphase polymerization of pyrrole between aqueous solutions of iron(ri1) salas and organic solutions of pyrrole separated by PVC films.* By this method, the structure of the blend could be altere2d by changing the organic solvent or the oxidant.The re1)orted conductivities of the films were in the range 0.1-10 S crn-l. Blends of polypyrrole with the elastomeric terpolynier of ethene, propene and 5-vinylnorborn-2-ene, EPDM, were obtained by incorporation of the oxidant into the rubher as filler, followed by exposure to pyrrole vapour.’ The host rubber film was prepared by calendering and this provides a method for large-scale production of blends of a rubber with a conductive polymer. Conductivities, however, were reported to be near lop7S cm-’. The electrode-coating method was used by Naoi and Osaka to prepare a blend of nitrilic rubber with polypyrrole." After rinsing the nitrilic rubber with an appropriate solvent the authors studied the remaining polypyrrole and observed no differences from a directly grown polypyrrole, suggesting no chemical interaction between the host and the guest polymers.The method, however, proved useful for obtaining polypyrrole with a controlled morphology. To use a conductive polymer in a battery or in an electro- chemical device, several conditions must be fulfilled, such as stability to several redox cycles, high chromatic contrast and high chemical stability. These parameters will be influenced by the electrode/electrolyte interface. In a solid-state device, where an ionically conductive polymer is used as electrolyte, the properties of this solid/solid interface are critical and could be optimized by increasing the compatibility between the polymeric electrode and electrolyte.The vulcanizable elastomeric copolymer of epichlorohydrin( l-chloro-2,3- epoxypropanej and ethylene oxide, commercially produced under the trade name of Hydrin-C, has been used previously as a solid electrolyte in a solid-state electrochromic device, indicating its good ionic conductivity." In this paper we describe the preparation of a blend of polypyrrole with this ionic conductor as a first step to obtain an electrode material compatible with the polymeric electrolyte material. Experimental The copolymer of epichlorohydrin and ethylene oxide used in this work (Hydrin C) was from Zeon Chemicals Inc.The blend was prepared by the working-electrode coating method; 100~1 of a 4% solution of Hydrin-C in chloroform was deposited over a 2.0cm2 area of the working electrode and evaporated producing a transparent 10 pm thick film. For spectroelectrochemistry measurements, a glass slide coated with tin oxide (ITO, from Nippon Sheet Glass, 100 a)was used as working electrode, in all other experiments a Pt sheet was used. Pyrrole (Aldrich, freshly distilled) was galvanostat- ically (0.5 mA cm-2, 45 s) polymerized in a two-electrode one- compartment cell using a 0.05 mol 1-l aqueous solution containing 0.025 mol 1-' sodium dodecyl sulfate (Aldricb). The electrochemical properties were studied by cyclic voltam- metry and chronoamperometry using a 0.5 mol 1-l aqueous KCl solution as electrolyte.Spectroelectrochemical experi- ments were performed by placing the three-electrode cell with optical windows in the sample compartment of a Hewlett-Packard HP8452 diode array spectrophotometer. Thermogravimetry (TG) and differential scanning calor- imetry (DSC) were performed using a DuPont 9900 thermal analysis system at a heating rate of 10°C min-' and under N, atmosphere. Scanning electron microscopy (SEMj was carried out using a JEOL JS-T300 instrument under 20 kV potential, using samples metallized with gold. An EMIC MEM-500 instrument interfaced to a PC was used for the stress-strain experiments, using a cross-head speed of 50 mm min-', a cell of 2 kgf? and five specimens per sample.Results and Discussion The Hydrin-C rubber film coated onto the working electrode is swollen by the aqueous monomer-electrolyte solution allowing polymerization to occur in its bulk, starting from the electrode/rubber interface and moving towards the rubber/ electrolyte interface, as observed in previous works. lo The first evidence for the formation of the blend is the darkening of the rubber film on the working-electrode surface. Following t 1 kgf= 9.806 65 N. J. MATER. CHEM., 1994, VOL. 4 the polymerization of pure polypyrrole, the conducting poly- mer is obtained in the oxidized/doped state. Gravimetric determination by rinsing the blend with chloroform indicated that the blend contained 10% of polypyrrole. After prep- aration it was characterized by electrochemical, spectroelectro- chemical and non-electrochemical methods.Characterizationby Electrochemical and Spectroelectrochemical Methods In Fig. l(u) and (b)we compare the cyclic voltammetry curves for the polypyrrole-Hydrin-C blend and pure polypyrrole prepared under the same experimental conditions. The curve for the blend shows very broad anodic and cathodic waves in contrast to that of pure polypyrrole. Two anodic and two cathodic waves can, however, be identified in both curves indicating two reversible redox processes. The differences in the current response can be assigned to the dependence on cation and anion diffusion rates from the electrolyte solution into the films, despite the ionic conductivity of the Hydrin-C rubber.The shifts in the anodic and cathodic peak potentials for the blends compared with those in pure polypyrrole are caused by the ohmic resistance of the rubber, as previously observed in other rubber-conductive polymer blend^.'^,'^ The amount of charge consumed by the blend during redox processes is much lower compared with that in pure polypyr- role, as would be expected from the low concentration of conductive polymer in the blend. Repeated double-potential-step chronoamperometric experiments were performed with the blend to study its stability to a large number of redox cycles. Pure polypyrrole doped with dodecyl sulfate was reported to retain its electro- chemical and electrochromic properties for 2 x lo4 double Fig. 1 Comparison of the cyclic voltammetry of (a)the blend polypyr- role-Hydrin-C and (b)polypyrrole-dodecycl sulfate, measured in an aqueous 0.5 mol 1-1 KC1 solution at 50 mV SKIin the -0.900-0.6OOV us.SCE range J. MATER. CHEM., 1994, VOL. 4 potential steps.14 The variation of the charge density of the blend during the first and 1400th double potential steps is shown in Fig. 2. There is a variation of the coulombic efficiency (expressed as the ratio between the oxidation and reduction charge densities) after 1400x lo3 steps, revealing a small degree of irreversibility in the chargeldischarge process. Also, the time necessary for the stabilization of the current in the reduction step increases as a function of the number of steps.The variation of the spectra of polypyrrole-dodecyl sulfate as a function of potential during cyclic voltammetry (2 mV s-', 0.5 mol 1-' aqueous KC1) is compared with that of a blend in Fig. 3. The spectral changes are qualitatively similar; however, a shift of the absorption maximum to lower energy in the oxidized state is observed upon comparing pure poly- pyrrole and the blend. This suggests that blending slightly affects the energy of the bipolaronic levels formed during the doping process. For the reduced, bleached state of the blend a higher absorptivity is observed in the visible/near-IR region in comparison to pure polypyrrole; this can be assigned to the absorption of the rubber component of the blend. A transmittance variation of 50% at 700nm was measured during a cyclic voltammetry experiment with a scan rate of 2 mV s-'.Characterization by Non-electrochemical Methods In Fig. 4 we compare TG curves for the sodium salt of dodecyl sulfate, pure polypyrroledodecyl sulfate, pure Hydrin-C and the blend. The steepest weight loss, observed in the curve for pure polypyrrole at ca. 180"C, is coincident with the pure dopant weight loss temperature, showing that the predomi- nant process is the thermal decomposition of dodecyl sulfate with the production of volatiles. The curve for Hydrin-C shows a pronounced weight loss at 300 "C, corresponding to dehydrochlorination and polyether-chain scission, followed by a slower weight loss with complete volatilization of all the residues at 800 "C. The blend contains predominantly Hydrin- C and its TG curve shows a first weight loss at 300°C with a lower slope, followed by a much slower loss assigned to the polypyrrole phase.The thermal degradation behaviour is mostly dominated by the more concentrated phase. The DSC curves compared in Fig. 5 show two phase transitions for pure crude Hydrin-C and for the blend, both associated with glass-transition temperatures. For pure Hydrin-C, the transition at -36°C is associated with the epichlorohydrin blocks, owing to the lower mobility of these blocks induced by the polarity of the chlorine atom. The other transition at -72 "C is associated with the blocks with higher mobility (ethylene oxide).In the case of the blend, the transition assigned to the ethylene oxide blocks of the copoly- mer is shifted to -62 "C, suggesting an increase in rigidity 4.0r tls Fig. 2 Variation of the charge density as a function of time during a double potential step applied to the polypyrrole-Hydrin-C blend: (a) first step, (b)1400th step 1801 0.31 h .-v) -C 0.24 v a 0.16 ([I42 02 0.09 00 A I&\0.76 h v)c..s0.65 4 .50.53 a0c $ 0.41 0 v)D ([I 0.29 00 Fig. 3 Variation of the spectra as a function of potential in a cyclic voltammetry experiment in an aqueous 0.5 mol 1-' KC1 solution at 2 mV s-' for (a) polypyrrole-dodecyl sulfate and (b) its blend with Hydrin-C I I I 1 I , -.0 200 400 600 800 TI% Fig. 4 Thermogravimetry ( 10"C min-I), comparing: (-) sodium dodecyl sulfate, (---) polypyrroleedodecyl sulfate, (-.-.-) Hydrin-C and the ( --) blend caused by its association with the polypyrrole chains. The transition assigned to the epichlorohydrin blocks is not shifted. The stress-strain curve for crude Hydrin-C shows the typical soft and weak behaviour of a crude elastomer, as indicated by the low modulus and high strain, Fig. 6. Dlespite the low concentration (10%) of polypyrrole in the blend, a J. MATER. CHEM., 1994, VOL. 4 -161 I 1I I-1 20I I I -20 I I I-70 I -30 TPC Fig. 5 Comparison of the differential scanning calorimetry curves (10"C min-') for: (a)pure Hydrin-C and (b)blend. Increasing negative values of heat flow indicates an endothermic process. 0 20 40 60 strain (Oh) Fig.6 Comparison of the stress-strain curves (50 mm min-') for: (a) pure Hydrin-C (crude) and (b)blend pronounced change in the stress-strain curve is observed with a pronounced increase in the modulus and decrease of the strain, showing a hardening and toughening of the material. This is assigned to the localization of the conductive polymer within the ethylene oxide blocks of the copolymer, reducing the mobility of the rubber chains. A previous study on the morphology of conductive polymer blends showed that the electrochemically polymerized chains grow perpendicularly to the working electrode surface." According to these authors and to our previous results with other blends, the conductive polymer grows from the working electrode surface towards the rubber/electrolyte interface.This effect can be observed in the scanning electron micrographs shown in Fig. 7. Comparing the surface of pure Hydrin-C [Fig. 7(a)],with the surface of a blend where the polymer- ization of pyrrole was performed for a time sufficiently short to have no polypyrrole on the rubber/electrolyte surface [Fig. 7(h)J, we observe that a small concentration of the conductive polymer is already sufficient to produce a detect- able change in the morphology of the surface of the material. When the polymerization time is extended, the morphology of the surface is similar to that of pure polypyrrole with the formation of globules, Fig.7(c). Conclusions Our results show that a partially miscible blend of polypyrrole and the copolymer of ethylene oxide and epichlorohydrin H 1 pm H10pm Fig. 7 Scanning electron micrographs of (a)pure Hydrin-C, (h)blend with low polypyrrole content and (c) blend with high polypyrrole content (Hydrin-C) can be prepared by an electrochemical method. This material retains the electrochemical and electrochromic properties of polypyrrole with a 10% loss of electrochromic contrast and lower stability to repeated redox cycles caused by the ohmic resistance of the rubber component of the blend. The mechanical properties, however, are very similar to those of a vulcanized rubber. We thank the following agencies for supporting our work: FundagBo de Amparo a Pesquisa do Estado de SBo Paulo (FAPESP, Proc. N.91/2561-9), Financiadora de Estudos e Projetos-Programa de Quimica para Electrhica, FINEP- PQE and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, CNPq. References 1 U. Eisele, Introduction to Polymer Physics, Springer-Verlag, Berlin, 1990, p. 159. J. MATER. CHEM., 1994, VOL. 4 1803 2 A. Echte, Handbuch der Weinheim, 1993, p. 663. Teckniscken Polymerckemie, VCH, 8 9 M. Nakata and H. Kise, Polym. J., 1993,25,91. R. A. Zoppi, M. I. Felisberti and M-A. De Paoli. J. Polym., Sci., 3 W. A. Gazotti Jr., V. F. Juliano and M-A. De Paoli, Polym. Purt A, Polym. Chem., 1994,32, 1001. 4 Drgrad. Strth.. 1993,42, 317. R. C. D. Peres, M-A. De Paoli and R. Torresi, Syntk. Met., 1992, 10 11 K. Naoi and T. Osaka, J. Electrockern. Soc., 1987, 134, 2479. E. Rezende Duek, M-A. De Paoli and M. Mastragostino, Ah. 48, 259. Muter., 1993,5, 650. 5 6 M-A. De Paoli, R. Waltman, A. Diaz and J. Bargon, J. Polym. Sci., Polym. Chern. Ed., 1985, 23, 1687. 0.Niwa, M. Hikita and T. Tamamura, Appl. Phys. Lett., 1985, 46,444. 12 13 14 E. L. Tassi and M-A. De Paoli, Polymer, 1992,33,2427 R. A. Zoppi and M-A. De Paoli, J. Electroanal. Clrem., 1990, 290,275. M-A. De Paoli, S. Panero, S. Paserini and B. Scrosati, Adc. Marer., 7 G. Casalbore-Miceli, G. Beggiato, A. Geri, A. Berlin, G. Pagani, G. Zotti and M-A. De Paoli, Mol. Crjist. Liq. Cryst., 1992, 219. 173. 1990,2,480. Paper 4/02080D; Receified 7th April, 1994

ISSN:0959-9428    

DOI:10.1039/JM9940401799

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

J. MATER. CHEM., 1994, 4( 12), 1805-1810 Electrochemistry of Poly(3-thiopheneacetic acid) in Aqueous Solution: Evidence for an Intramolecular Chemical Reaction Philip N. BartIett* and Darryl H. Dawsont Department of Chemistry, University of Southampton, Southampton, UK SO9 5NH Electrochemical oxidation of 3-thiopheneacetic acid in dry acetonitrile leads to the formation of a conducting polymeric film. These films can be cycled between oxidised and reduced forms in acetonitrile, but on oxidation in water or methanol are converted to a passive film. This process is accompanied by the passage of approximately two electrons for every monomer unit within the film. Based on the electrochemistry and FTIR studies of the process, a mechanism for the electrochemical passivation of the polymer is proposed involving the formation of an intermediate cyclic lactone and subsequent breakdown by reaction with the solvent. Electropolymerised films of the corresponding methyl ester, methyl 34hiopheneacetate, are not subject to the same electrochemically driven passivation reaction in watcsr.Conducting polymer films prepared by the electrochemical polymerisation of heterocyclic monomers have attracted much attention over the past The electrochemical oxi- dation and reduction of these polymers is accompanied by the movement of charge-balancing counter-ions into and out of the film to maintain electroneutrality. In so-called ‘self- doped’ polymers the anion required for electroneutrality in the oxidised, conducting, form of the polymer is covalently bound to the polymer ba~kbone.~ Examples of polymers of this type include p~lypyrroles~,~ withand polythi~phenes~~~ covalently attached sulfonate groups prepared from the corre- sponding sulfonated pyrrole and thiophene monomers.If, instead of using strongly acidic sulfonic acid substituents, conducting polymers are produced with carboxylic acid sub- stituents then this self-doping process will be pH-dependent in aqueous solution because of the weakly acidic nature of the carboxylate. As a result the electrochemistry of the con- ducting polymer film is then pH-dependent and the redox process is, in general, accompanied by the ingress or egress of protons. Pickup” was probably the first to report the aqueous electrochemical behaviour of a polymer with a carboxylic acid substituent. In his study of the electrochemistry of poly(3- methylpyrrole-4-carboxylic acid) the potentials of the oxi- dation and reduction peaks (Epa and EPc)were found to depend upon the pH of the aqueous electrolyte.Subsequently, Delabouglise and Garnier reported a preliminary study on the electrochemical properties of poly( 3-carboxymethylpyr- role) films.” They found that the anodic peak potential for these films shifted on average by ca. 60mV per pH unit in the region between pH 0 and 6, indicating that one proton was lost for each electron removed in the oxidation of the polymer. Other examples of conducting polymers exhibiting pH-dependent aqueous electrochemistry include polyani-line,12,13 which requires protonation of the partially oxidised form in order to attain electronic conductivity, and poly(5- carboxyindole).l4 Our interest has been in the applications of conducting polymers in bioelectro~hemistry,~~~~~and for this reason we are interested in the electrochemistry of these films in aqueous solution.Although polythiophenes have been widely studied, stable electrochemical responses of polythiophene films are not generally observed in aqueous solution and this has proved to be the major barrier in the exploitation of these polymers. The limited aqueous electrochemistry has mainly been attributed to the hydrophobicity of the polythiophene” t Present address: Department of Chemistry, University College, 20 Gordon Street, London, UK WClH OAJ.chains and the relatively high oxidation potential of these polymers when compared to polypyrroles. Sunde et a1.’83’9 were able to perform cyclic voltammetry of poly( 3-mrbthylthio- phene) films in aqueous solutions containing “I3-and C104- but were unable to repeat the measurements in SO,’--and C1 --containing solutions. This presumably reflelcts differ- ences in the nucleophilicity of the anions. Covalent substitution has also been employed as it strategy to improve the aqueous electrochemistry of polythrophenes. For example, when polyether groups2’ are substituted at the b-position of the thiophene ring the overall hydrophobicity of the polythiophene is reduced, facilitating the free niovement of counter-ions within the film.Based on these observations one might expect that covalently bound carboxylic actd groups would also reduce the hydrophobicity of the polyt hiophene and thus facilitate stable aqueous electrochemistry. Ir addition the carboxylic acid substituted polymer would be expected to show pH-dependent electrochemistry. In this paper ~e present results of a study of the growth, in acetonitrile, and the aqueous electrochemistry of poly (3-thiopheneacetic id)"-^^ and its esters using FTIR spectroscopy to charac,erise the resulting films. Experimental Materials 3-Methylthiophene (Aldrich, 99 + %) was distilled under reduced pressure and stored over activated 3 A inolecular sieves. 3-Thiopheneacetic acid (Aldrich, 98YO)was recrystal- lised from distilled water and dried under high vacuum.(Used 3-thiopheneacetic acid was recovered from acetonit rile solu- tion and background electrolyte by reducing the solution under vacuum followed by recrystallising twice from distilled water .) Methanol (Fisons, analytical reagent) was distilled over calcium hydride and used immediately without furthe c storage. Methyl( 3-thiopheneacetate) was synthesized in the following manner. 3-Thiopheneacetic acid (4 x 5 g) was dis.;olved in dried methanol (100 cm3 each) with a drop of concentrated hydrochloric acid and refluxed. The reaction was followed using thin-layer chromatography with a 10:1 dichloro-methane (Aldrich, Reagent Grade)-methanol system with a spray for detecting esters (1% vanillin in concentrated sulfuric acid with a trace of ethanol).After complete reaction the reaction solutions were combined and reduced under vacuum and dissolved in diethyl ether (Fisons, analytical reagent) (50 cm-’). The organic phase was washed with saturated sodium hydrogencarbonate solution (3 x 30 cm -3) tnd dried 1806 over anhydrous magnesium sulfate before being reduced under vacuum and pumped under high vacuum. The ester was obtained as a clear liquid (80-90% yield) and used without further purification. Methyl (3-thiopheneacetate): dH (ppm, 400 MHz, CDCI,, Me&): 3.65 (2 H, s, H5), 3.69 (3 H, s, H7), 7.03 (I H, c, H3), 7.14 (1 H, c, H1), 7.27 (I H, c, H2).6, (ppm, 100 MHz, CDCI,, Me,CI): 35.3 (C'), 51.7 (C'), 122.6 (C'), 125.4 (C3), 128.2 (C'), 133.3 (C'), 171.2 (C6).m/z (EI) 156 (SO%, M") 97 [lOO%, (C,H,S)CH,]. IR (o/cm-', thin layer): 3100 (m, d-H stretch), 2800-3000 (ms, aliphatic C-H stretches), 1741 (vs, C=O stretch), 1440 (s, CH, sym. def.), 1350-1550 (m, aromatic ring stretches), 1150 [s, CC(=O) -0 stretch]. (d= 1.26 g ern-,). The corresponding ethyl, propyl and butyl esters of thiophene acetic acid were prepared by similar routes. Acetonitrile (Aldrich, BDH and Rathburn, HPLC grade) was distilled over calcium hydride, under a dry nitrogen blanket, for at least 24 h and was used immediately without further storage. Methanol (Aldrich, anhydrous 99 + %) was used without any further purification.Aqueous solutions were prepared using water from the Whatman WR50 RO purifi- cation system pumped through a carbon filter (Whatman Still Plus) giving a conductivity in the range 0.1-1.0 pS cm-'. Tetraethylammonium tetrafluoroborate (TEAT) (Aldrich, 98%) was recrystallised from methanol (Fisons, analytical reagent) and dried under high vacuum. Electrochemical Equipment Electrochemical experiments were carried out using a commer- cial potentiostat (Thompson Electrochem Ltd., Ministat) coupled with an external 16-bit digital potential sweep gener- ator (Thompson Electrochem. Ltd., Miniscan). Electrochemical data were recorded using an X Y-t chart recorder (Bryans/Gould, 60 000 series) or a digital voltmeter (Keithley model: 197). All electrochemical experiments were performed inside a water-jacketed electrochemical cell thermo- statted at 25 & 0.2 'C.Aqueous solutions were degassed directly in the cell by bubbling oxygen-free nitrogen through the solution for at least 20 min. A platinum rotating disc working electrode (A=0.385 cm2, Oxford Electrodes) encased in Kel-F was employed in most studies. Initial polishing was achieved using individual Hyprocel lapping cloths (Engis) sprayed with 6, 3 and 1 pm diamond lapping spray (Engis). Before each experiment the electrodes were initially polished with 1 pm alumina-water slurry followed by 0.3 pm alumina- water slurry, both on medical cotton wool, to give a mirror finish. All potentials were measured against a in-house con- structed saturated calomel electrode (SCE) incorporating a low-porosity ceramic frit (gift from Kent Industrial Measurements Ltd.).The reference electrodes were checked against a commercial SCE (Radiometer) for deviations >6 mV. Counter-electrodes were constructed from (1x 4) cm2 platinum gauze spot-welded a thick platinum wire. The coun- ter-electrode was regularly washed in Whatman RO water and was cleaned before each experiment by heating it over a blue Bunsen flame until the platinum glowed orange and the flame had no colours corresponding to contaminants. FTIR Spectroscopy Two FTIR spectrometers were utilised in this work, a Perkin- Elmer 1720X (maximum resolution 2 cm-') and a Nicolet 510P (maximum resolution 0.8 cm-l) interfaced with a Philips 386 microcomputer running PCIR software (Nicolet Computers Ltd.).Ex situ reflection-absorption spectra of polymer films deposited on electrodes were recorded using specular reflectance accessory (Specac) at 21" to the surface J. MATER. CHEM , 1994, VOL. 4 normal. A special electrode support was designed to hold the disc electrode in the correct position within the reflectance accessory. Results and Discussion Growth and Non-aqueous Electrochemistry of Poly (3-methylthiophene), Poly (3-thiopheneacetic acid) and Poly [methyl( 3-thiophene acetate)] Films of poly( 3-methylthiophene) were prepared for compari- son with the substituted polythiophenes. The> were grown from solutions of 3-methylthiophene (0.1 rnol dm-,) in aceto-nitrile containing TEAT (0.1 mol dmP3) by stepping the potential from 0.0 to 1.65 V at a polished stationary platinum disc electrode.The cyclic voltammetry of the films formed in acetonitrile solutions containing TEAT (0.1 mol dm -,) was consistent with previously reported results.23 Films of poly( 3-thiopheneacetic acid) were grown from solutions of 3-thiopheneacetic acid (1.0 mol dni-,) in aceto-nitrile containing TEAT (0.1 rnol drn-,) by cyclic voltammetry between 0.0 and 1.8 V at a polished stationary platinum disc electrode. Films were generally grown by sweeping the poten- tial between the preset limits four times at 100 mV s-' (Fig. 1). The success of growth depended heavily upon the purity of the solution, with aged solutions producing poorer quality films, presumably because of the presence of increased concen- trations of water.Cycling the potential of the films between 0.0 and 1.4 V in solutions of acetonitrile containing TEAT (0.1 mol dm-3) resulted in passivation after several (cu. 10) scans. However, cyclic voltammetric data recorded on the first scan immediately after growth gave an approximately linear correlation between sweep rate (v) and peak height (ips) (r=0.999, n=4 with E,, between 1.2 and 1.3 V). The anodic peak potential, Epa,for oxidatioii of the mon- omeric 3-thiopheneacetic acid in acetonitrile (1.99 V) was found to be similar to that for 3-methylthiophene under the same conditions (1.96 V), indicating that the acetic acid group has very little direct inductive effect on the oxidation potential of the thiophene ring.In contrast, the peak potential for the oxidation of poly( 3-thiopheneacetic acid) is shifted around 0.4 V anodic of the corresponding oxidation potential for poly( 3-methylthiophene) films under the same conditions. This suggests that there are significant steric effects acting within the poly(3-thiopheneacetic acid) which increase the oxidation potential of the film' over and above any effects which might be accounted for by the electron-withdrawing effect of the substituent. Films of poly [methyl( 3-thiophene acetate)] were grown I I I 0.0 0.5 1.0 1.5 2.0 EN vs. SCE Fig. 1 Growth of a poly( 3-thiopheneacetic acid) film by cyclic voltam- metry at a platinum electrode (A=0.385 cm') in a solution of 3-thiopheneacetic acid (1.0 rnol dm-3) in dry acetonitrile containing TEAT (0.1 mol dm-3) (sweep rate, I)= 100 mV s-') J.MATER. CHEM., 1994, VOL. 4 1807 -1.5 I I I 0.0 0.5 1.o 1.5 EN vs. SCE Fig. 2 Cyclic voltammetry of a poly(methy1 3-thiopheneacetate) film in acetonitrile containing TEAT (0.1 rnol dm-3) at sweep rates, u= 20,40, 60, 80 and 100 mV s-' from acetonitrile solutions of methyl( 3-thiophene acetate) (0.1 mol dm-3) containing TEAT (0.1 mol dm-3) by cycling the potential between 0.0 and 1.7 V at a polished stationary platinum disc electrode. Films could also be grown by stepping the potential of the electrode to 1.7 V in acetonitrile solutions of the monomer at concentrations of as little as 15 mmol dm-3.However, the best quality films were obtained by potential cycling. In contrast to the behaviour found for films of poly(3- thiopheneacetic acid), the cyclic voltammetry of poly(methy1 3-thiopheneacetate) films is very stable in acetonitrile, (Fig. 2), giving a linear i,, us. u relationship (r=0.999, n=5). The limiting values for the E,, and E,, for poly(methy1 3-thio- pheneacetate) are Epa=1.16 V and EPC=1.11 V, which are as high as the corresponding poly( 3-thiopheneacetic acid) values. This again suggests low planarity of the heterocyclic rings' of the monomers within the polymer. The ethyl, propyl and butyl esters, and their corresponding polymers, exhibit very similar electrochemistry to the methyl ester.25 Characterisation of Poly (3-thiopheneacetic acid) and its Esters by FTIR The ex situ reflection-absorption FTIR spectrum of a poly( 3-thiopheneacetic acid) film held at 0.0 V in acetonitrile containing TEAT (0.1 mol drn-,) and then removed from solution and dried is shown in Fig.3. The broad absorption extending down from 4000cm-' is probably the result of direct electronic transitions within the conducting polymer. Below 2000 cm-' there are a number of IRAV bands. A very strong carbonyl band is observed at 1709 cm-' ,corresponding to the H-bonded acid dimer in the polymer. Medium-strength bands are observed between 1300 and 1590 cm-', correspond- ing to aromatic and ring-ring stretches. The PC-H out-of-plane bend is observed as a weak band at 835 cm-' which is m0.3 2 0,0 e5 0.2 I0 2l 0.1m shifted to higher wavenumber than the corresponding PC-H out-of-plane bend for poly( 3-methylthi0phene).'~ There do not appear to be any significant aC-H out-of-plane bending absorptions in the spectrum (observed at 690 and 790cm-' in p~lythiophene~~), indicating that there are few P or P-P defects in the polymer, even when grown at relatively high potentials.This may be due to the steric directing effects of the attached acetic acid groups.' The reflection-absorption FTIR spectrum of fully reduced poly(methy1 3-thiopheneacetate) is shown in Fig. 4. Similar spectra are obtained from electropolymerised films of the ethyl, propyl and butyl esters25 except that they shoh increas-ing intensities for aliphatic C-H stretches between 2800 and 3000 cm-' as the aliphatic chain length increases.Very little aliphatic C-H stretching is observed in the poly(methy1 3- thiopheneacetate) spectrum. The poly(methy1 3-thio-pheneacetate) spectrum also contains a band at 1440 cm-' corresponding to a symmetric CH, deformation which is not observed in the other spectra. All the ester-substituted poly- mers have carbonyl peaks corresponding to the ester groups25 between 1740 and 1730cm-' and a peak at 1150cm-' corresponding to an acetate C-C(=0)-0 symmetric stretch. It is evident that there are also weaker underlying bands between 1300 and 1500 cm-', corresponding to aro- matic ring stretching and ring-ring stretching.The PC-H out-of-plane bending in all the spectra occurred as a weak band at 835 cm-' with no visible aC-H out-of-plane bending. The spectra described above clearly demonstrate the pres- ence of the relevant functional groups within the polymer structure. A slight difference in the carbonyl peaks from monomer to polymer is obtained. This is quite comnion and occurs in other types of polymers due to steric packing effec ts.26 Aqueous Electrochemistry of Poly (3-rnethylthiophene), Poly( 3-thiopheneacetic acid) and Poly(methy1 3-thiopheneacetate) The voltammetric behaviour of a film of poly( 3-methylthio- phene) cycled between 0.0 and 0.9 V at 20 mV s-' in degassed aqueous potassium nitrate (0.1 rnol dm-3) was consistent with that in the literat~re;'~,~~ over the first few cycles the amount of charge passed during oxidation or reduction of the film (Qcv) decreased and then, with repeated cycling, stabilised.In contrast, when a film of poly( 3-thiopheneacetjc acid) was placed in a degassed aqueous solution of pogassium nitrate (0.1 rnol dmP3) and cycled between 0.0 and 1.4 V at 10 mV s-' a large current was passed on the first anodnc cycle and then subsequent cycles showed passivated behaviour (Fig. 5). The ratio of the charge passed in the first anodic sweep in aqueous solution Qcv(aqueous) to the charge passed for oxidation of the same film in acetonitrile Q,,(acetonitrile) was 9.1k0.2: 1. This corresponds to around 2 e for each monomer unit within the polymer film, based on a doipancy' 0.0 10.0: 4000 3000 2000 1000 2000 1600 1200 800 400 waven u m be r/cm-' waven umberkm-' Fig.3 Reflection-absorption FTIR spectrum of a fully reduced film Fig. 4 Reflection-absorption FTTR spectrum of a fully reduced film of poly( 3-thiopheneacetic acid) of poly(methy1 3-thiopheneacetate) 1808 J. MATER. CHEM . 1994, VOL. 4 between 0.0 and 1.2 V, with a sweep rate of 10 mV s-', in degassed aqueous potassium nitrate (0.1 rnol dnxP3) solution. 0.6i Again passivation was observed upon the second cycle. However, in this case the amount of charge passed in passiv- ation of the film was approximately the same as the charge passed in oxidation of the film in acetonitrile, i.e. ca. 1 e for a every four monomer units within the polymer chain.The E2 reflection-absorption FTIR spectra of poly(methy1 3-thio- 0.21 pheneacetate) after cycling in aqueous solution shows the presence of a new band at 1650cm-' which we ascribe to a,p-unsaturated ketone groups formed by nucleophilic attack on the oxidised polymer by ~ater.~~,~* Comparison of our 0.0Iresults for poly(methy1 3-thiopheneacetate) and poly( 3-thio- pheneacetic acid) films indicates that the large charge associ- 0.c 0.5 1 .o 1.5 EN vs. SCE Fig. 5 Passivation of a poly( 3-thiopheneacetic acid) film during cyclic voltammetry between 0 and 1.5 V (us. SCE) in degassed aqueous potassium nitrate (0.1 mol dm-3) solution (sweep rate, o= 10 mV s-') of 6=0.25 for the polymer.It is clear that upon oxidation in the aqueous solution an electrochemical reaction occurs which destroys the conductivity of the polymer. The reflection-absorption FTTR of poly( 3-thiopheneacetic acid) before and after cyclic voltammetry in aqueous potass- ium nitrate is shown in Fig. 6. Following voltammetry in aqueous solution the intensity of the carbonyl band at 1709 cm-' is significantly decreased and the intensity of adsorption at 1650 cm-' is enhanced relative to the intensities of the aromatic and ring-ring stretches between 1300 and 1500 cm -'. The band at 1650 cm -which increases in relative intensity with passivation probably corresponds to an a$-unsaturated ketone group within the polymer formed by nucleophilic attack of water upon the polymer during oxi- dati~n.~~,~*Based on the amount of charge passed in the oxidation of the polymer in aqueous solution we estimate that almost every monomer has been converted to the a$-unsaturated ketone form during the initial cycle.This is a remarkable finding because we might have expected a lower degree of passivation to have destroyed sufficient of the film conductivity to prevent total oxidation within the film during the first cycle. We return to this point below. The electrochemistry of poly(methy1 3-thiopheneacetate) was studied in degassed aqueous solution to provide a com- parison to poly( 3-thiopheneacetic acid) since both have simi- lar E,, values in acetonitrile solutions. A film of poly(methy1 3-thiopheneacetate) was studied by cyclic voltammetry r ated with passivation of the poly( 3-thiopheneacetic acid) films is directly related to the presence of the carboxylic acid substituent on the chain.Electrochemistry of Poly (3-methylthiophene) and Poly (3-thiopheneacetic acid) in Methanol To investigate the electrochemical passivation of poly( 3-thiopheneacetic acid) further we examined the electrochemis- try of films of the polymer, grown in acetonitrile, in methanol containing TEAT (0.1 mol drnp3). Methanol has similar properties to acetonitrile but is more nucleophilic. This pre- vents polymer growth but not polymer electrochemistry. A film of poly(3-methylthiophene) grown for 60s was studied by cyclic voltammetry in a degassed solution of methanol between -0.3 and 1.0 V.The electrochemistry was stable and consistent with the electrochemistry of the film in acetonitrile (once allowance was made for the for difference in liquid-junction potentials for the SCE in the two solvents, this shifted the voltammetry by ca. 0.1 V). There were no changes in the reflection-absorption FTIR spectra of the polymer before and after cyclic voltammetry in methanol and the subsequent electrochemistry in acetonitrile remained unchanged. This demonstrates that, on the timescale of our experiments, methanol does not attack poly( 3-methylthio- phene) during oxidation and reduction. In direct contrast when a film of poly( 3-thiopheneacetic acid), grown in the manner previously described for four cycles, was studied by cyclic voltammetry between 0.0 and 0.3r 0.0 I I 0.00i2000 1600 1200 8002000 1600 1200 800 400 wavenumbedcm-' waven um ber/cm-' Fig.7 Reflection-absorption FTIR spectra of poly ( 3-thiopheneaceticFig. 6 Reflection-absorption FTIR spectra of poly (3-thiopheneacetic acid) before (a) and after (b)passivation by electrochemical oxidation acid) before (a) and after (b)the passivation shown in Fig. 5 in methanol J. MATER. CHEM., 1994, VOL. 4 0 0 I -2e, -H'I /-. -*H+ /e-, -2H+ 111 0 0 /-, -2H' 0 0 N 0 0 0 0 OR 0 HOR v further solvdysis leadingto passive film Fig. 8 Reaction scheme proposed to account for the electrochemical passivation of poly(3-thiopheneacetic acid) (I) in water or mcthanol 1.6 V at 20 mV s-l in a degassed solution of methanol contain- ing TEAT, passivation was observed following the first anodic scan.The passivation of the film was again, as in the experi- ments with this polymer in aqueous solution, accompanied by the passage of a significant charge corresponding to ca. 2 e for each monomer unit within the polymer. Inspection of the reflection-absorption FTIR spectra of the film before and after cyclic voltammetry in methanol (Fig. 7) showed that the carboxylic acid functionality had been totally replaced by a methyl ester functionality with a C=O stretch at 1734 cm-I and a CH, symmetric deformation band at 1440 cm-' as well as other bands associated with the methyl ester. We assign the additional band at 1098 cm-' to C-OH stretch of residual methanol within the film.Thus it appears that in methanol the electrochemical passivation of the film is accompanied by the esterification of the carboxylic acid groups. This is unexpected since esterifications in methanol usually require more forcing conditions such as low pH and prolonged heating. Discussion The electrochemistry of poly( 3-thiopheneacetic acid) shows some unusual features which are not found in the electrochem- istry of poly( 3-methylthiophene) or poly(methy1 3-thio-pheneacetate). We suggest that this behaviour can be explained by the reaction scheme shown in Fig. 8. In dry acetonitrile poly( 3-thiopheneacetic acid) can be cycled electrochemically between its reduced (I) and oxidised (11) forms.However, if the carboxylic acid groups can be deprotonated, for example in water or methanol, we postulate that oxidation of the polymer can be followed by intramolecu- lar reaction and further oxidation to form a cyclic lactone (TIT). This process does not destroy the conductivity of the polymer so that the process can continue until all the monomer units within the film are converted into the postulated lactone form (IV). Overall this consumes two electrons for every monomer unit in the film so that in total nine times as much charge is passed to oxidise the film in water or methanol as is passed in dry acetonitrile. The poor stability of poly(3- thiopheneacetic acid) electrochemistry in acetonitrile, as com- pared to that for poly( 3-methylthiophene) or poly(methy1 3- thiopheneacetate), is presumably the result of traces of water leading to some deprotonation and lactone formation.We then suggest that the postulated cyclic lactone (IV) is itself unstable with respect to solvolysis and that the lactone rings open to give unsaturated ketones (V) and to destroy the conductivity of the film. In water this produces carboxylic acid groups, but in methanol the solvolysis of the lactone would yield the corresponding methyl ester. This scheme is consistent with the ex situ reflection-absorption FTIR studies of the films before and after passivation and with the charge passed to passivate the film, although we have no direct evidence from this work for the intermediacy of the cyclic lactone.The fact that almost all the monomer units within the film undergo reaction indicates that the electrochemical oxidation and cyclic lactone formation must occur more rapidly than the subsequent solvolysis which destroys the J. MATER. CHEM., 1994, VOL. 4 conductivity of the film. If this were not the case the loss of conjugation in the polymer would prevent further charge propagation and electrochemical oxidation in the bulk of the film. In the case of both poly( 3-methylthiophene) and poly(me- thy1 3-thiopheneacetate) the formation of a cyclic lactone is not possible and therefore these polymers are not subject to the same type of electrochemical passivation. To the best of our knowledge this is the first example of this type of electrochemically driven passiva tion, and substi- tution, of a conducting polymer to be reported.In principle other reactions of this type should be possible and offer an interesting way to prepare thick, insulating polymer films at electrode surfaces. References 1 Handbook of Conducting Polymers, ed. T. A. Skotheim, Marcel Dekker, New York, 1986. 2 S. Bruckenstein and A. R. Hillman, J. Phqs Chem., 1988,92,4837. 3 G. Bidan, B. Ehui and M. Lupowski, J. Phys. D, 1988,21, 1043. 4 A. Patil, Y. I. Kewone, F. Wudl and A. Heeger. J. Am. Chem. Soc., 1987,109,1858. 5 A. Patil, Y. I. Kewone, N. Basescu, N. Colaneri, J. Chen, F. Wudl and A. Heeger, Synth. Met., 1987,20, 151. 6 W. Wernet, M.Monkenbusch and G. Wegner. Mukromol. Chem. Rapid Commun., 1984,5, 157. 7 A. Patil, Y. I. Kewone, F. Wudl and A. Heeger, J. Am. Chem. Soc., 1987,109,327. 8 S. Basak, K. Rajeshwar and M. Kaneko, Ancil. Chem., 1990, 62, 1407. 9 N. S. Sundereson, S. Basak, M. Pomerantz and J. R. Reynolds, J. Chem. Soc., Chem. Commun., 1987, 621. 10 P. G. Pickup, J. Electroanal. Chem., 1987,225,773. 11 D. Delabouglise and F. Garnier, New J. Chem., 1990, 15,233. 12 W. S. Huang, B. D. Humphrey and A. G. MacDiarmid, J. Chem. Soc., Faraday Trans. I, 1986,82,2385. 13 G. Inselt and G. Harangi, Electrochim. Actu, 1990,35, 27. 14 P. N. Bartlett, D. H. Dawson and J. Farrington, J. Chem. SOC., Faraday Trans. 1, 1992,823,2685. 15 P. N. Bartlett and J. M. Cooper, J. Elecrrotmd. Chem., 1993, 362, 1. 16 P. N. Bartlett and J. Farrington, J. Electroanul. Chem., 1989, 261, 471. 17 G. Kossmehl and M. Niemitz, Synth. Met., 1991, 41, 1065. 18 S. Sunde, G. Hagen and R. Odegard, Synth. Met., 1991,43,2983. 19 S. Sunde, G. Hagen and R. Odegard, J. Electrocrnal. Chem., 1991, 138,2561. 20 J. Roncali, L. H. Shi, R. Garreau, F. Garnier and M. Lemaire, Synth. Met., 1990,36,267. 21 W. J. Albery, F-B. Li and A. R. Mount, J. Electroanal. Chem., 1991,310,239. 22 F. B. Li and W. J. Albery, Electrochim. Actu, 1991,37, 293. 23 F. B. Li and W. J. Albery, Langmuir, 1992,8, 645. 24 J. L. Sauvajol, D. Chenouni, J. P. Lere-Porte, C. Chorro, B. Moukala and J. Petrissans, Synth. Met., 1990.38, 1. 25 D. H. Dawson. Ph. D. Thesis, University of Warwick, 1992. 26 H. W. Siesler and K. Holland-Moritz, Infrtired and Raman Spectroscopy of Polymers, Marcel Dekker, New York, 1980. 27 F. Beck, P. Brown and M. Oberst, Ber. Bunsenges. Phys. Chem., 1987,91,967. 28 E. W. Tsai, S. Basak, J. P. Ruiz, J. R. Reynolds and K. Rajeshwar, J. Electrochem. Soc., 1989,136, 3683. 29 J. Heinze, Synth. Met., 1991,43, 2805. Paper 4/02095B; Received 8th April, 1994

ISSN:0959-9428    

DOI:10.1039/JM9940401805

出版商:RSC    

年代:1994

数据来源: RSC