Optical properties of side-chain liquid crystal copolymers of monosubstituted cholesteryl itaconate and a non-chiral mesogen

1995 ◽  
Vol 73 (11) ◽  
pp. 1811-1817 ◽  
Author(s):  
J.M.G. Cowie ◽  
H.W. Hunter
Keyword(s):  
Itaconic Acid ◽  
Liquid Crystalline ◽  
Glassy State ◽  
Side Chain ◽  
Ultraviolet Region ◽  
Scanning Calorimetry ◽  
Selective Reflection ◽  
Cholesteric Phase ◽  
Crystalline Polymers ◽  
Derivatives Of

New mono- and disubstituted cholesteryl derivatives of itaconic acid have been prepared and their thermotropic liquid crystalline behaviour examined. The monosubstituted derivative has been homopolymerized, and also copolymerized with a non-chiral mesogen 4-cyanophenyl-4′-(6-acryloyl oxyhexyloxy) benzoate. Examination of the series of copolymers prepared, using differential scanning calorimetry and hot-stage polarizing microscopy, showed that when the content of the cholesteryl itaconate was high, both a smectic-A phase (SA) and a cholesteric phase (N*) were present. It was found that the SA phase could be eliminated by lowering the content of the cholesteryl itaconate in the copolymers, giving samples that displayed only the N* phase over a much wider temperature range. The samples in the N* phase also exhibited selective reflection of visible light that changed from short to long wavelengths as the samples were cooled from the isotropic melt. These colours can be locked into the glassy state of the polymer by quenching below the glass transition temperature, but only if the SA phase is absent. It was also noted that at high contents of the cholesteryl itaconate the selective reflection appears to occur in the ultraviolet region. Keywords: itaconic acid, copolymers, liquid crystalline polymers, cholesteric phases, selective reflection.

Synthesis and Phase Behavior of Chiral Liquid Crystal Elastomers Containing Cholesteryl Group

2012 ◽  
Vol 554-556 ◽  
pp. 807-810 ◽  
Author(s):  
Ying Gang Jia ◽  
Kun Ming Song ◽  
Bao Yan Zhang
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Crosslinking Agent ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Selective Reflection ◽  
Cholesteric Phase ◽  
Liquid Crystal Elastomers ◽  
Cholesteric Liquid Crystalline

The synthesis of new side chain cholesteric liquid crystalline elastomers (ChLCEs) containing the cholesteric monomer M and the flexible non-mesogenic crosslinking agent C, is described. The selective reflection of light for M was characterized with UV/Visible/NIR. The phase behavior and mesomorphism were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers P1– P8is discussed. The ChLCEs exhibit elasticity, reversible phase transitions, and cholesteric Grandjean texture. The experimental results demonstrate that the glass transition temperature and isotropic temperature of ChLCEs decrease with increasing the content of crosslinking unit, but the cholesteric phase is not disturbed.

Synthesis and Physical Properties of π -Conjugated Polymers Containing Mesogenic Group

1996 ◽  
Vol 425 ◽  
Author(s):  
Y. Watanabe ◽  
N. Koide
Keyword(s):  
Aromatic Compound ◽  
Liquid Crystalline ◽  
Oxidation Potential ◽  
Side Chain ◽  
Mesogenic Group ◽  
Scanning Calorimetry ◽  
Polymer Backbone ◽  
Crystalline Polymers ◽  
Lower Oxidation ◽  
Chain Type

AbstractNovel side chain type liquid crystalline polymers, polythiophene and poly(aryleneethynylene) [PAE], containing a mesogenic group in the side chain were synthesized. Polythiophene derivatives were obtained by dehalogenative polycondensation with zero-valence nickel complex under mild condition. PAE type polymers were obtained by coupling dihalo aromatic compound with diethynyl aromatic compound. Their thermal properties were examined by differential scanning calorimetry, optical microscopy and X-ray diffractometry. All polymers exhibited a smectic or nematic mesophase depending upon the polymer backbone and pendant mesogenic group. Polythiophene derivatives exhibited electrochemical activity. Annealing polythiophene derivatives led to a lower oxidation potential and a higher conductivity. The degree of the orientation of the polymer backbone was supported by polarized UV-vis measurement. An effective conjugated length became longer by introducing thiophene rings into the polymer backbone. A high quantum yield of fluorescence was observed for PAE type polymers.

Synthesis and Properties of Side Chain Azobenzene Liquid Crystalline Polymers

2013 ◽  
Vol 781-784 ◽  
pp. 436-439
Author(s):  
Dan Shu Yao ◽  
Jun He ◽  
Hai Yan Wang ◽  
Mei Tian ◽  
Xiao Zhi He ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Graft Polymerization ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Temperature Ranges ◽  
Mesomorphic Properties

A series of new azobenzene side chain liquid crystalline polymers were synthesized by two different azo mesogen monomers, 4-((4-(ethoxycarbonyl) phenyl) diazenyl) phenyl 4-(allyloxy) benzoate (M1) and (4-((4-(ethoxycarbonyl) phenyl) diazenyl) phenoxy) methyl acetyl 4-(allyloxy) benzoate (M2). All polymers (P1~P8) were synthesized by graft polymerization using polymethyl hydrosiloxane as backbone. Their chemical structures were confirmed by FTIR and 1HNMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that P1~P8 exhibited thermotropic liquid crystalline properties and revealed nematic thread texture with wide mesophase temperature ranges. The temperatures when 5% weight loss occurred were higher than 305°C, which declared that the synthesized azobenzene liquid crystalline polymers had a high thermal stability.

Synthesis of Ferroelectric Liquid Crystalline Polymers by Ring Opening Polymerization

1996 ◽  
Vol 425 ◽  
Author(s):  
C. S. Hsu ◽  
C. J. Lee
Keyword(s):  
Ring Opening ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Ring Opening Polymerization ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystalline Polymers ◽  
Smectic A ◽  
Smectic C

AbstractThe synthesis of two series of side-chain liquid crystalline polyoxetanes and polyoxiranes containing 4-alkanyloxybiphenyl-4′ -yl (2S,3S)-2-chloro-3-methylvalerate side groups is presented. Differential scanning calorimetry, polarizing optical microscopy, and X-ray diffractometry reveal smectic mesomorphism for all obtained polymers. Most of the prepared polyoxetanes present smectic A and chiral smectic C phases. The polyoxetane containing tweleve methylene units in the spacer is the only one showing two enantiotropic smectic A and B phases. All of the obtained polyoxiranes display two enantiotropic smectic A and B phases. Although the polyoxetane and polyoxirane backbones are more flexible than the polymethacrylate backbone, side-chain crystallization do not occur in any of the synthesized polymers.

Effect of Two Diferrent Mesogens on Liquid-Crystalline Properties of Chiral Side-Chain Liquid-Crystalline Polysiloxanes

2011 ◽  
Vol 415-417 ◽  
pp. 1395-1398
Author(s):  
Ji Wei Wang ◽  
Jun Qing Zi ◽  
Li Xian He ◽  
Guang Yong Chen ◽  
Yan Zhong Yang
Keyword(s):  
Liquid Crystalline ◽  
Proton Nuclear Magnetic Resonance ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
Long Wavelength ◽  
Crystalline Polymers ◽  
Chemical Structures ◽  
Nuclear Magnetic Resonance Spectra ◽  
Temperature Ranges

Abstract. A series of liquid crystalline polysiloxanes were synthesized by cholesteric LC monomer and nematic LC monomer. The chemical structures and liquid-crystalline properties of the monomers and polymers were characterized by various experimental techniques including Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra (1H-NMR), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) , X-ray diffraction measurements (XRD) and polarizing optical microscopy (POM). All the liquid crystalline polymers showed liquid crystalline properties with wide mesophase temperature ranges. For the polymers bearing only of one nematic LC monomer, it showed nematic phase, while others showed cholesteric phase. With increase the content of nematic LC monomer in the polymers from P1 to P7, the glass transition temperature and the isotropic temperature increased on heating circles. Reflection spectra of cholesteric mesophase of the series of polymers showed that the reflected wavelength shifted to long wavelength with increase content of nematic LC monomer in the polymers in the polymer systems, suggesting that helical pitch (P) become long.

Study on the Properties of Mesogenic Monomer Exhibiting Blue Phase and Synthesis of Side-Chain Liquid-Crystalline Polysiloxanes

2011 ◽  
Vol 399-401 ◽  
pp. 1071-1074
Author(s):  
Ying Li ◽  
Guang Cheng Zhang ◽  
Shui Yuan Shao
Keyword(s):  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Smectic A ◽  
Crystal Polymer ◽  
New Type ◽  
Blue Phase

A new type of Side-Chain Liquid-Crystalline Polysiloxanes was synthesized by graft polymerization, using (Trans, trans)- 4-propyl-4’-vinyl-bicyclohexane(3HHV) with platelet texture of a blue phase as mesogenic monomer. Microstructure of monomer and polymer were analyzed by polarizing optical microscopy and X-ray diffraction. Thermal properties of monomer and polymer were researched by differential scanning calorimetry. Meanwhile, spherulite texture of polymeric smectic A phase of liquid crystal polymer was revealed in the cooling cycle by polarizing optical microscopy, and this texture was so uncommon that can hardly be found in the liquid crystalline polymers.

Cholesteric Cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes

2014 ◽  
Vol 809-810 ◽  
pp. 308-312 ◽  
Author(s):  
Ying Li ◽  
Liang Zhang ◽  
Meng Jie Chang
Keyword(s):  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Molecular Structures ◽  
Liquid Crystalline Phase ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
H Nmr ◽  
Flexible Spacer

Two new kinds of Cholesteric cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes (PAand PB) were synthesized via hydrosilylation reaction of polymethyl hydrogen siloxane with cyclohexane mesogenic monomers (MAand MB). The yield of PA, PBwere 71.6%, 82.5% and 81.0%, respectively. The molecular structures of MAand MB, PAand PBwere investigated by Fourier transform infrared spectroscopy (FTIR) and hydrogen-nuclear magnetic resonance spectra (1H-NMR). The corresponding liquid crystalline phase type was also observed by polarizing optical microscopy (POM) and X-ray diffraction (XRD). The liquid crystalline phase behavior and thermal properties of the polymers were analyzed by differential scanning calorimetry (DSC). Results showed that MAand MBexhibited multicolor platelet texture of a blue phase and cholesteric phase, and the Tmand Tiof MAand MBincreased with the increasing flexible chain length. The mesophase temperature range of PAand PBwas broader than that of MAand MB. PAexhibited a rare nematic phase----spherulite texture of polymeric smectic A phase. PBwere of cholesteric and nematic---- cholesteric phase. The Tmand Tiof PAand PBincreased with the increasing flexible spacer groups.

A New Series of Two-Ring-Based Side Chain Liquid Crystalline Polymers: Synthesis and Mesophase Characterization

2013 ◽  
Vol 66 (6) ◽  
pp. 667 ◽  
Author(s):  
Goddeti Siva Mohan Reddy ◽  
Tanneru Narasimhaswamy ◽  
Jarugala Jayaramudu ◽  
Emmanuel Rotimi Sadiku ◽  
Konduru Mohana Raju ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Variable Temperature ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Molecular Weights ◽  
Smectic C ◽  
Phenyl Rings ◽  
Alkoxy Groups

A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings and an ester linking unit. All the polymers were characterised by hot-stage polarising optical microscopy, differential scanning calorimetry, variable temperature X-ray diffraction, thermogravimetric analysis, and gel permeation chromato-graphy. The polymers were found to be liquid crystalline. The nematic and smectic A (SA) phases were observed for the homologues with short-terminal chains (C2 and C6), whereas the homologues with longer chains (C8 to C12) exhibited a smectic C phase. The thermal stability of the polymers was found to be in the range of 293 to 326°C and the molecular weights of the polymers were found to vary from 6 × 103 to 1.3 × 104.

scholarly journals Phase Transitions of Side Chain Liquid Crystalline Polymers Having a Terminal Alkyl Chain.

1993 ◽  
Vol 50 (9) ◽  
pp. 687-691 ◽  
Author(s):  
Seiji UJIIE ◽  
Tamami FUKUI ◽  
Kazuko HIGAKI ◽  
Satoshi TAKAHASHI ◽  
Kazuyoshi IIMURA
Keyword(s):  
Phase Transitions ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Crystalline Polymers
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