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 Phase Behavior of Polysiloxane Nematic Liquid Crystal Elastomers

2012 ◽  
Vol 535-537 ◽  
pp. 1185-1188 ◽  
Author(s):  
Ying Gang Jia ◽  
Kun Ming Song ◽  
Bao Yan Zhang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
One Step ◽  
Liquid Crystal Elastomers ◽  
Reversible Phase

This paper describes the synthesis of new side chain nematic liquid crystalline elastomers (LCEs) by a one-step hydrosilication reaction. 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 – P8 was discussed. The nematic LCEs exhibit elasticity, reversible phase transitions, and nematic thread texture. The experimental results demonstrate that the glass transition temperature and isotropic temperature of nematic LCEs decreased with increasing the content of crosslinking unit.

Synthesis and Mesomorphic Behavior of Chiral Liquid Crystalline Elastomers Derived from (S)-(-)-2-Methyl-1-Butanol

2013 ◽  
Vol 750-752 ◽  
pp. 863-866 ◽  
Author(s):  
Ying Gang Jia ◽  
Lu Juan Han ◽  
Ting Sun ◽  
Xiao Zhi He
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Crosslinking Agent ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
X Ray ◽  
Butyl Group ◽  
Crystal Polymer ◽  
Reversible Phase

The synthesis of new chiral monomer 4-((4-(allyloxy) benzoyl) oxy) phenyl (S)-4-(2-methylbutoxy) benzoate (Mch), crosslinking agent hexane-1,6-diyl diacrylate (CA), and liquid crystal polymer elastomers (E1-E7) containing (S)-(-)-2-Methyl-1-butyl group is presented. The phase behavior and mesomorphism of the polymers were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction. The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers was discussed. The chiral LCEs (E1-E7) exhibited elasticity, reversible phase transitions, and cholesteric Grandjean texture. The experimental results demonstrated that the glass transition temperature and isotropic temperature of Chiral LCEs decreased with increasing the content of crosslinking agent, but the cholesteric phase was not disturbed.

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.

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.

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

Novel cholesteric liquid crystalline elastomers containing dimer type nematic and chiral liquid crystalline side-chains

RSC Advances ◽  
2016 ◽  
Vol 6 (85) ◽  
pp. 81902-81912 ◽  
Author(s):  
Ying Jiang ◽  
Yuehua Cong ◽  
Baoyan Zhang
Keyword(s):  
Liquid Crystalline ◽  
Crosslinking Agent ◽  
Side Chain ◽  
Side Chains ◽  
Hydrosilylation Reaction ◽  
Cholesteric Liquid Crystalline

A new set of cholesteric side chain liquid crystalline elastomers (ChLCEs) E1–E7 were graft copolymerized by hydrosilylation reaction with poly(methylhydrogeno)siloxane, nematic monomer (M1), chiral monomer (M2), and crosslinking agent (CL).

Synthesis and phase behavior of chiral liquid crystalline polymeric networks derived from menthol

2012 ◽  
Vol 24 (8) ◽  
pp. 673-682 ◽  
Author(s):  
Ying-Gang Jia ◽  
Jian-She Hu ◽  
Dan Li ◽  
Qing-Bao Meng ◽  
Xia Zhang
Keyword(s):  
Phase Behavior ◽  
Near Infrared ◽  
Polymer Networks ◽  
Crosslinking Agent ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Cholesteric Phase ◽  
Temperature Range ◽  
Chemical Structures

The synthesis of new chiral monomer 4-(menthyloxyacetoxy- benzoyloxy)biphenyl-4′-(2-(undec-10-e noyloxy)ethoxy)benzoate (ML), crosslinking agent 4-(undec-10-enoyloxy)biphenyl-4′-(2-(undec-10-enoyloxy)ethoxy)benzoate (CA), and liquid crystal polymer networks (E1−E5) containing menthyl group is presented. Their chemical structures and phase behavior were characterized with Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), elemental analyses, polarizing optical microscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), and X-ray diffraction. The selective reflection of light for ML was investigated with ultraviolet/visible/near infrared (UV/Visible/NIR). By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, MLcould form mesophase and show a chiral smectic C phase, cholesteric phase and cubic blue phase. CA displayed a smectic A phase and nematic phase. The polymer networks containing less than 12 mol% of the crosslinking units showed reversible cholesteric phase transition, wide mesophase temperature range, and excellent thermal stability. With increasing the content of crosslinking unit, the corresponding Tg increased, the Ti decreased, and the mesophase temperature range narrowed for E1−E5. TGA showed that the Td(5%) was greater than 330°C for E1−E5.

scholarly journals Phase transition behavior of silicone based liquid crystalline polymers

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
R. N. Jana ◽  
H. Bhunia ◽  
C. Im
Keyword(s):  
Phase Transition ◽  
Liquid Crystalline ◽  
Crosslinking Agent ◽  
Transition Temperatures ◽  
X Ray Diffraction ◽  
Phase Transition Behavior ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Transition Behavior ◽  
Ft Ir

AbstractPhase transition behavior of silicone based liquid crystalline (LC) polymers with variable isotropic transition temperatures (Ti), synthesized from poly(methyl hydrosiloxane), 10-undecenoic acid based crosslinking agent and cholesterol based side chain mesogen, was studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) measurements. The chemical structure of the mesogenic monomer and the LC polymers were confirmed by Fourier transform infra-red (FT-IR) spectroscopy and 1HNMR spectroscopy. DSC studies showed that the glass transition temperatures (Tg) and Ti of the LC polymers decreased with increasing proportion of mesogenic crosslinking agent at its low proportion and at its higher proportion Ti disappeared completely indicating that the polymeric chains had less chance to orient in the network structure. The results were consistent with the XRD and POM studies.

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