Thermotropic liquid crystalline polymers

Шибаев, В. П.; Kozlovsky, Mikhail V.; Beresnev, L. A.; Blinov, L. M.; Plat, N.A.

doi:10.1007/bf00263142

Cited by 206 publications

(32 citation statements)

References 3 publications

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“…1 As already noted, the analogous moleinto comblike macromolecules promotes a dipolar ordering with tilted smectic phase formation. 8 cules and the polymers prepared often demonstrate the presence of a half or one water molecule This paper reports the synthesis and the LC properties of these materials studied by differential per pyridinium unit. However, products can be easily obtained in an anhydrous state by heating scanning calorimetry (DSC), optical microscopy, and X-ray diffraction.…”

Section: Introductionmentioning

confidence: 99%

Effect of smectogenicity of the ionic groups on the thermotropic liquid crystalline behavior of pyridinium and poly(4-vinylpyridinium) salts quaternized with mesogenic groups

Chovino

Frère

Guillon

et al. 1997

J. Polym. Sci. A Polym. Chem.

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Section: Introductionmentioning

confidence: 99%

Effect of smectogenicity of the ionic groups on the thermotropic liquid crystalline behavior of pyridinium and poly(4-vinylpyridinium) salts quaternized with mesogenic groups

Chovino

Frère

Guillon

et al. 1997

J. Polym. Sci. A Polym. Chem.

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“…SA J we detected pyroelectric effects in the range of St phase existence. 15 The temperature dependences of the pyroelectric coefficient y and spontaneous polarization P 8 calculated on integrating the curve y = dP 8 jdT are presented at The relaxation time r of the spontaneous polarization is about 100 fJ.S well below the S(!->SA transition and reveals fast growth in the vicinity of this point reaching 1 ms. This attests the presence of the soft mode in molecular motions at the transition, similar to the ferroelectric soft mode in solid ferroelectrics near the Curie point.…”

Section: Meso Phases Of Polymers With Side Mesogenic Groupsmentioning

confidence: 99%

Polymeric Liquid Crystals—Problems and Trends

Platè

Talrose

Freidzon

et al. 1987

Polym J

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ABSTRACT:The problems of synthesis, structure and physico-chemical properties of synthetic liquid crystalline polymers whose macromolecules contain mesogenic fragments in the side chains are discussed. A detailed structural analysis of these polymers which form SA, S8 , Sc, SF, and other straight and inclined smectic phases is given, along with ferroelectric properties. Structural transformations in these polymers influenced by temperature and external mechanical and electrical fields cause polymorphism of liquid crystalline polymers including reversible transition from smectic to nematic phase. Conformational transitions and relaxational processes in nematic polymers by the action of an electrical field including phenomena of electrohydrodynamical instability and recording and storage of information are discussed. Attention is paid to the polymers of cholesteric structure which can be obtained by inducement of helicity due to the copolymerization of chiral monomers with comb-like systems for which nematic phase in polymeric state is typical. Optical properties of these polymers, degree of helicity, helix pitch and the wavelength of the selective reflection of the light can be regulated in wide limits using a synthetic approach, temperature, and electrical field influence.KEY WORDS Liquid Crystals I Nematic I Smectic I Cholesteric I Helix Pitch 1 Mesophase I Electrohydrodynamic Instability I Chiral Monomer I Ferroelectric Properties I Spacer I Texture I Up to:..date physics and chemistry of polymeric liquid crystals is an intensively developing field of polymer science. Every year more than hundred new thermotropic polymeric liquid crystals are synthesized. The structure of liquid crystalline (LC) polymers and their behavior in outer fields, reology and the properties of LC solutions are studied. The theoretical aspects of the LC ordering are also developing. New applications of LC systems which combined the mechanical properties of polymeric materials and structure features of liquid crystals are being sought. rying mesogenic groups in side chains. 1 A wide range of different mesomorphic structures is known to be formed by branched or so-called comb-like polymers. The variety of structures depends on the flexibility of the backbone, on the length and flexibility of the spacer and on the chemical nature of mesogenic fragments and attachment bridges. 2

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“…2 Moreover, chirality in smectic (Sm) liquid crystals gained a pivotal position in the history of LCs after the discovery of the ferroeletricity in chiral SmC molecules by Meyer and coworkers. 3,4 However, the first chiral SCLCP was reported in 1984 by Shibaev and et al 5 Since then, a wide range of candidate materials has been synthesized and their mesomorphic and electro-optical properties have been studied as well. [6][7][8][9] Together with the interest in the liquid crystal area, we have synthesized and studied the correlation structureproperty in a series of different thermotropic liquid crystalline polyacrylates.…”

Section: Introductionmentioning

confidence: 99%

Structure-property relationships of smectic liquid crystalline polyacrylates as revealed by SAXS

Pereira¹,

Ritter²,

Gonçalves³

et al. 2006

J. Braz. Chem. Soc.

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A influência da estrutura química dos grupos mesogênicos e do tamanho dos grupos espaçadores, no comportamento de fase de uma série de cristais líquidos poliméricos de cadeia lateral (SCLCP), foram estudados utilizando-se espalhamento de raios-X a Baixo Ângulo (SAXS) e Microscopia Ótica de Luz Polarizada (POM). Análises do arranjo das mesofases em amostras não orientadas e orientadas por ação do campo magnético são descritas. O papel do tamanho do espaçador lateral no empacotamento local e na largura da camada esmética determinados nas mesofases SmA e SmC é elucidado. Os ângulos θ formados entre os grupos mesogênicos e a normal às camadas nas mesofases SmC foram determinados. Um estudo a respeito do grau de ordem em função da temperatura, para os polímeros esméticos foi possível através de medidas de SAXS. Uma ordenação particular em um dos SCLCPs estudados é relacionada com a coexistência de duas fases distintas.The influence of the chemical structure of the mesogenic groups and the length of the spacer groups on the phase behavior in a series of side-chain liquid crystalline polyacrylates (SCLCP) have been studied using Small Angle X-ray Scattering (SAXS) and Polarized Optical Microscopy (POM). Analyses of the mesophase arrangement in unaligned and aligned samples by magnetic field are reported. The role of the spacer length on the local packing and on the thickness of the layers encountered in the SmA and SmC mesophases is elucidated. The tilt angles θ of the mesogenic cores related to the normal of the layers in the SmC mesophases are measured. A study about the degree of order as a function of temperature for the smectic polymers was possible using SAXS measurements. A particular arrangement in one of the studied SCLCPs is related to the coexistence of two different phases.

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Thermotropic liquid crystalline polymers

Cited by 206 publications

References 3 publications

Effect of smectogenicity of the ionic groups on the thermotropic liquid crystalline behavior of pyridinium and poly(4-vinylpyridinium) salts quaternized with mesogenic groups

Effect of smectogenicity of the ionic groups on the thermotropic liquid crystalline behavior of pyridinium and poly(4-vinylpyridinium) salts quaternized with mesogenic groups

Polymeric Liquid Crystals—Problems and Trends

Structure-property relationships of smectic liquid crystalline polyacrylates as revealed by SAXS

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