摘要:

Besides the usual acrylates, 4-[4-(n-acryloloxyalkyloxy)phenyl]benzoic acids (4a-4c), new acrylates containing two units of acrylic acid, 4-{4-[n-(3-acryloloxypropionyloxy)alkyloxy]phenyl}benzoic acid (5a-5c), are formed by the esterification of acrylic acid and 4-[4-(n-hydroxyalkyloxy)phenyl]benzoic acid (3). All the mesogenic monomers which were synthesized from the corresponding acrylates (4a-5c) and 4-hydroxyphenyl 2(S)-[2(S)-methylbutoxy]propionate (2) exhibit the enantiotropic S*cand SAphases. The S*cphase temperature range is up to 44°C. The range of spontaneous polarization and response time for those monomers is between 34 and 85nC cm-2, and 55 and 460μs, respectively. Some liquid crystal side chain polymers containing2are switchable in the presence of an electric field. A spontaneous polarization of 72nC cm-2and a response time of 2.6 ms were the best results obtained for those polyacrylates.

ISSN:0267-8292    

DOI:10.1080/02678299408036527

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Liquid crystal alignment is studied using propagating optical mode techniques for a cell with a high surface tilt SiO alignment. The director configuration is determined for both the nematic and smectic A phases. In the nematic phase a uniform splay across the cell is demonstrated, as predicted by continuum theory. In the smectic A phase the structure is seen to be nearly uniform in the central region of the cell with large splay in boundary layers of about 0.5 μm thickness. The reason for this appears to be competition between the tilted surface alignment forces and internal forces within the bulk of the smectic A layer which would induce a homogeneous configuration.

ISSN:0267-8292    

DOI:10.1080/02678299408036528

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We present a theoretical study of two-wave mixing in smectic A liquid crystals (SALC) due to the resonant interaction of the electromagnetic (EM) waves through the second sound (SS), which is a new type of the cubic non-linearity. It is shown that a parametric amplification of one EM wave by the other occurs. Explicit expressions for the EM and SS wave amplitudes are obtained, which appear to be of the kink and transverse spatial soliton form, respectively. It is also shown that the SS wave creates flexoelectric polarization and space charge. The estimated gain is one or two orders of magnitude greater than the gain for the stimulated Brillouin scattering in isotropic organic liquids. The theoretical results obtained may be used as a basis for an experimental investigation of SS high frequency behaviour.

ISSN:0267-8292    

DOI:10.1080/02678299408036529

出版商:Taylor & Francis Group    

年代:1994

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:10.1080/02678299408036516

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor