摘要:

Mesomorphic copolysiloxanes, which combine ‘normal’ end-on linked chiral mesogenic units inducing S*cphases and side-on fixed chromophores were prepared. The interplay of the different orientational tendencies of these moieties, which are perpendicular (end-on linked mesogenic groups) or parallel (side-on fixed chromophores) to the polymer chain, lead to a strong destabilization of the S*cphase. However, copolymers with up to about 10 mol % of chromophores still show a smectic C* phase. FTIR measurements show that both moieties orient parallel to each other and perpendicular to the polymer chains. These copolymers are interesting to consider as coloured guest-host S*cmaterials for coloured displays or as pyro-electric detectors.

ISSN:0267-8292    

DOI:10.1080/02678299508036708

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The chiral structure of the anomalous smectic phase recently observed in chiral copolymers has been studied by optical methods. The phase is amorphous, but shows a short range order, as a combination of smectic A and cholesteric structures. This phase is presumed to possess locally the TGBAstructure.

ISSN:0267-8292    

DOI:10.1080/02678299508036709

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The first high polarization ferroelectric main chain liquid crystalline polymers have been synthesized via hydrosilation polyaddition using α, ω-dihydro(tetramethyldisiloxane) and chiral, low molar mass mesogenic compounds bearing at each end an olefinic group. They exhibit broad, chiral smectic C and smectic A mesophases. Aligned samples have been obtained using a combination of surface and mechanical effects, giving opportunities for fully characterizing the electro-optical properties of the polymers. Very high polarizations have been measured: 600 nC cm−2at room temperature.

ISSN:0267-8292    

DOI:10.1080/02678299508036710

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

(S)-Hexakis(4-(4′-(6-methyl)octyloxy)biphenoxy)cyclotriphosphazene (SMOCP) was synthesized in a search for new ferroelectric liquid crystalline compounds. We found an enantiotropic ferroelectric smectic C* phase between 419 and 441 K in SMOCP by using polarizing microscopy and DSC measurements. The spontaneous polarization was estimated to be -130.5 μCm−2at 437.6 K, several times larger than that of DOBAMBC ((S)-2-methylbutyl 4-(4′-decyloxybenzylidene)aminocinnamate.

ISSN:0267-8292    

DOI:10.1080/02678299508036711

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Smectic mesophase behaviour in perfluorooctyl side chain polyesters with hydrocarbon comonomers has been investigated by DETA and X-ray diffraction at different temperatures. The polymers show clear transitions from the solid to the fluid mesophase and from the mesophase to the isotropic liquid.

ISSN:0267-8292    

DOI:10.1080/02678299508036712

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A thin plastic cell containing the ferroelectric liquid crystal ZLI3654 (4 μm) was placed edge-on to a pin-hole collimated horizontal X-ray beam. In this way, the smectic layers were brought into register. Subsequently, triangular voltage waves with various peak (Vp) values were applied across the cell and diffraction photos were obtained during the application of the alternating voltage. Up toVp= ± 30 V, no significant movements in the initial tilted orientation of the smectic layers with respect to the surfaces (chevrons) could be observed. During the application ofVp= ± 32 V an increasing fraction of the smectic layers changed their initial tilt angle with respect to the cell surfaces to make larger tilt angles. At a slightly higher voltage, the layers became upright (bookshelf structure). Upon removing the voltage and short circuiting the cell, the quasi-bookshelf structure was sustained. The new method described here can be used in combination with a fast detector for time resolved experiments.

ISSN:0267-8292    

DOI:10.1080/02678299508036713

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0267-8292    

DOI:10.1080/02678299508036697

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor