摘要:

AbstractTwo categories of thermochromic polythiophene derivatives have been identified, which are dependent upon the nature and the position of the substituents. A molecular mechanism is proposed that can explain the thermally induced optical transitions observed in these materials.

ISSN:1022-1360    

DOI:10.1002/masy.19940870103

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe polymer analogous aromatization of double‐stranded Diels‐Alder polymers to give fully unsaturated, all‐carbon ladder polymers by means of dehydration and dehydrogenation is described. The polymers obtained were characterized by solid state13C NMR spectro

ISSN:1022-1360    

DOI:10.1002/masy.19940870104

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe inclusion of monomeric α,ω‐diamines and related polymers by cyclodextrins was investigated by1H NMR spectroscopy. As a result we found, that for both monomers and polymers the rate of the inclusion process largely depends on the degree of protonation of the amino groups of the gu

ISSN:1022-1360    

DOI:10.1002/masy.19940870105

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractFunctional silicone copolymers containing one or several types of pendant ester groups including a benzophenone or a thioxanthone chromophore, and/or a tertiary amine were used to prepare novel photo‐initiating systems based on the phenone ‐ amine photogeneration of radicals. The influence of the nature and relative amounts of the functional pendant units on the overall efficiency of the various initiating systems was evaluated by measuring the rate of polymerization of an acrylate based composition. By comparing the results obtained from different combinations of polymeric or low molecular weight reactants, a neatpolymer effectinducing a greater initiation efficiency is evidenced, especially when a polysiloxane containing only aromatic carbonyl ester groups is associated with free 4‐dimethylaminobenzoic esters as hydrogen donors. Time‐resolved spectroscopy performed with thioxanthone functional systems indicates that the favourable effect on the apparent polymerization rate is not correlated with the rate of quenching of the triplet excited state by a tertiary amine. Thepolymer effectcan rather be explained by the microheterogeneity of the distribution of the partners in the complex initiation

ISSN:1022-1360    

DOI:10.1002/masy.19940870106

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe method of variable angle x‐ray photoelectron spectroscopy has been applied to transferred monolayers of a new cellulose derivative. The results support a model for the monolayer in which the cellulose backbone lies flat on the substrate and the sidechains extend perpendicular to the surface. Furthermore, a significant portion of the substrate surface is found to be bare, indicating that the transferred monolayer contains major defects in the form of hole

ISSN:1022-1360    

DOI:10.1002/masy.19940870107

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe microstructure and thermal stability of Langmuir‐Blodgett‐Kuhn multilayers containing rod‐like polyglutamate copolymers having flexible aliphatic side chains have been studied with x‐ray and neutron reflectometry. Upon annealing at 84°C the multilayer structure changes in a manner which is dependent upon the degree of orientation of the rod‐like backbones and therefore upon the flow dynamics of the deposition. A sample deposited with a highly convergent flow loses the bilayer structure induced by deposition, whereas samples with less highly aligned backbones may not undergo this relaxation

ISSN:1022-1360    

DOI:10.1002/masy.19940870108

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractInterface structures of C60 and polymeric phthalocyanines (GeOPc and AlFPc) were analyzed by high resolution electron microscopy. C60 was crystallized making its {111} ‐plane parallel to the surface of tetragonal phthalocyanines as on other substrates. This may be due to strong tendency of C60 to make its closed‐pack layer parallel to the surface during crystallization. In addition to this plane orientation, an axial orientation was observed; Theanddirections of C60 orient along thedirections of phthalocyanines. It can be concluded from observations that the lattice‐matching between the corresponding repeating distances of C60 and phthalocyanines is an important factor governing the orient

ISSN:1022-1360    

DOI:10.1002/masy.19940870109

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractTriblock copolymers could form supramolecules in either polar or nonpolar solvents at appropriate concentration and temperature ranges or in the presence of additives. The association properties and the structure of supramolecules of PEO‐PPO‐PEO and PPO‐PEO‐PPO (PEO and PPO refer to poly(oxyethylene) and poly(oxypropylene), respectively) triblock copolymers in xylene and/or water were investigated by using light scattering, small‐angle neutron scattering, and small‐angle X‐ray scattering. The association process of aqueous solution or water‐rich ternary systems was entropy driven and temperature played an important role. The additive, e.g., water in the oil‐rich ternary system, played a very important role on the micellization of PEO‐PPO‐PEO, e.g., Pluronic L64, in xylene. The micelles had a core‐shell structure and the micellar shell was rather heavily solvated. At high copolymer concentrations, large aggregates with a lamellar structure was formed and the amount of large aggregates increased with increasing copolymer concentrati

ISSN:1022-1360    

DOI:10.1002/masy.19940870110

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThree actual problems connected with the collapse transition of polyelectrolyte gels in poor solvent are reviewed. (i) The first topic is the appearance of microstructures for polyelectrolyte gels in poor enough solvents. Three reasons for microsegregation are discussed: effect of polyelectrolyte – hydrophobic competition, effect of the formation of multiplets from ionic pairs in the ionomer regime and the effect of partial formation of glassy kinetically frozen polymer rich regions. (ii) Second we analyze the interaction of the gels with polymers which are capable to form complexes with the gel chains. Main experimental results are presented for poly(methacrylic acid) gels interacting with poly(ethylene oxide), (iii) Finally, we consider the problem of interaction of polyelectrolyte gels with the sufactants. The micelle formation of surfactants inside the gel and its consequences for the conformational properties of the gel are discussed in detai

ISSN:1022-1360    

DOI:10.1002/masy.19940870111

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractAn overview is given on recent studies of latices by small‐angle x‐ray scattering (SAXS). It is demonstrated that SAXS‐studies performed at different contrast (contrast variation) allows the full elucidation of the fine structure of the particles down to a size‐scale of a few nanometers. Examples are given including studies on core‐shell latices composed of polystyrene (PS) and poly(methyl methacrylate) (PMMA) as well as of carboxylate

ISSN:1022-1360    

DOI:10.1002/masy.19940870112

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY