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In this paper, first series of liquid crystal polymers (PF) synthesised by hydrosilylation of monomer containing furan group (MA), monomer containing cholesterol group (MB), monomer containing D (+)-camphoric acid group (MC) and monomer containing cyano-group (MD), catalysed by platinum catalyst. Another series of liquid crystal polymers (EF) is synthesised by the Dies-Alder reaction of the former series and cross-linker containing bismaleimide group. The results of Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance(1H NMR) showed the successful preparation of various monomers as well as polymers. The thermal properties of two series were characterised by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). We observed dramatic colour changes and Grand-jean textures of polymers using polarised optical macroscope (POM). The results of POM and selective reflection showed that both series of polymers are cholesteric liquid crystals. In the latter series, crosslinking by Diels-Alder reaction can make the liquid crystal better oriented, which can maintain their wonderful liquid crystal (LC) texture and selective reflection, and at the same time, it has a certain regulation effect on the appearance of cholesteric Grand-jean blue texture. The results of X-ray diffraction (XRD) further proved the two series of polymers are cholesteric liquid crystals. [ABSTRACT FROM AUTHOR]

In this study, a series of cholesteric liquid crystal elastomers (ZSD series) was synthesised by hydrosilylation reaction among monomer ML1 containing cholesteryl group, monomer ML2 as the crosslinking agent, monomer ML3 containing D(+)-camphoric acid group. The chemical structures and mesogenic properties of monomers and elastomers were studied by conventional testing methods. By characterising the liquid crystal elastomers, it was found that they all showed colourful Grandjean texture, good elasticity and high thermal stability. For the ZSD series, the values of Tg first decreased and then increased and the values of Ti always decreased with the change of the content of chiral liquid crystal monomers, and all elastomers had the wide mesophase temperature ranges (ΔT). ZSD1-ZSD3 had selective reflection in the visible light region, while the observation for ZSD4-ZSD7 could only be observed under the appropriate external pressure. The effect of the novel chiral monomer (ML3) on the properties of elastomers had been investigated. [ABSTRACT FROM AUTHOR]

We synthesized two series of cholesteric liquid-crystal elastomers by hydrosilylation among monomers MA containing a cholesteryl group, MB (MC) containing a phenolic hydroxyl group and MD as the crosslinker. The chemical structures of all the monomers and LCEs were confirmed by 1H NMR and FT-IR. We explored the mesomorphic properties and phase behaviours by TGA, DSC, POM, and XRD. All the LCEs presented elasticity, reversible phase transition, and high thermal stability. For two series of LCEs, the glass transition temperature increased slowly, and the isotropic transition temperature increased obviously. PA-I-PA-V and PB-I-PB-IV displayed selective reflection and colourful Grandjean texture, but PA-VI, PB-V, and PB-VI needed external pressure to show them. [ABSTRACT FROM AUTHOR]

The cholesteric polysiloxanes (PLQ series) were obtained by reacting cholesteric monomer and phenolic hydroxyl monomer in different ratios with polysiloxanes. The chiral azo-containing polysiloxanes liquid-crystalline elastomers (LCEs) were synthesised by esterifying PLQ series with acyl acid of azo diacid catalysed by 4-dimethylaminopyridine (DMAP). The chemical structures and mesomorphic properties of monomers and polymers were confirmed by conventional spectroscopic methods. The elastomers displayed elastic properties, reversible phase transition and high thermal stability. The Tg values changed irregularly and Ti values decreased at the beginning and then increased afterwards. The chiral azo-LCEs showed colourful textures and a Grandjean texture could be observed, which exhibited a red shift with increasing content of azo moiety. PLQ2-PLQ6 exhibited selective reflection in the visible light region, but PLZ1-PLZ4 can only observe selective reflection when appropriate mechanical pressure was imposed on the polymers. The PLZ series was carefully investigated by ultra violet-visible spectroscopy. [ABSTRACT FROM AUTHOR]

A new series of side-chain chiral liquid crystalline elastomers derived fromM1(cholest-5-3-ol(3β)-4-(2-propen-yloxy)]benzoate) andMC(2,5-[3,5-bis(4-(3-(4-(allyloxy)phenyl)propanoyloxy)benzoyloxy)benzoic acid]isosorbide diester). The structures of monomers and elastomers measured by using Proton Nuclear Magnetic Resonance Spectra (1H-NMR) and Fourier transform infrared spectroscopy (FTIR) separately are consistent with our design.IIP~VIPall appeared blue Grandjean (GJ) texture on the heating cycle or cooling cycle. The glass sheets ofIIP~VIPwere made under 150°C and measured its ultraviolet–visible spectrophotometry by PerkinElmer Lambda 950 instrument (Shelton, CT, USA).IIP~VIPall have absorptions at about 481~483 and 561~562 nm. The optical activities were measured at different temperatures on heating and cooling cycles. And the blue selective reflection ofIIP~VIPon the round glass sheet can be seen. The elastomers containing less than 6 mol% of the crosslinking units displayed elasticity, reversible phase transition and high thermal stability. The glass transition temperatures reduced first and then increased, the isotropisation temperatures and the mesophase temperature ranges increased first and then decreased with increasing content of crosslinking unit. The thermogravimetric analysis (TGA) results showed that the temperatures at which 5% weight loss occurred (Td) were greater than 310°C for all the polymers. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the effect on phase behaviors of side-chain chiral liquid crystalline elastomers of the different rigidity of the chiral crosslinker. It investigated the chemical structure of the monomers and polymers. It found that the isotropization temperature values of PII series are higher than those of PI series.

A series of new chiral smectic liquid crystalline elastomers was prepared by graft polymerization of a nematic monomer with a chiral and non-mesogenic crosslinking agent, using polymethylhydrosiloxane as backbone. The chemical structures of the monomers and polymers obtained were confirmed by FTIR and 1 H NMR. The mesomorphic properties were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy and X-ray diffraction. Monomer M 1 showed a nematic phase during heating and cooling. Polymer P 0 exhibited a smectic B phase; elastomers P 1– P 3 showed the smectic A phase, P 4– P 6 showed a chiral smectic C(SmC*), and P 7 displayed stress-induced birefringence. Elastomers containing less than 15?mol?% M 2 displayed elasticity, reversible phase transitions with wide mesophase temperature ranges, and high thermal stability. With increasing content of the crosslinking unit, glass transition temperatures first increased, then fell, then increased again; isotropization temperatures and mesophase temperature ranges steadily decreased. [ABSTRACT FROM AUTHOR]

Abstract: Several novel chiral side-chain liquid crystalline (LC) polysiloxane resins containing epoxy groups and mesogenic components have been graft copolymerized by a one-step hydrosilylation reaction with poly(methylhydrogeno)siloxane, an epoxy monomer 2-(allyloxymethyl)oxirane, and chiral fluorinated liquid-crystalline monomers 4′-(4-(allyloxy)benzoyloxy)biphenyl-4-yl 6-(perfluorooctanoyloxy)hexahydrofuro[3,2-b]furan-3-yl adipate and 4′-(4-(undec-10-enoyloxy)benzoyloxy)biphenyl-4-yl 6-(perfluorooctanoyloxy)hexahydrofuro[3,2-b]furan-3-yl adipate. The synthesized epoxy resins are cured using 4,4′-diaminodiphenyl-methane in mesophase state under a magnetic field to obtain crosslinked oriented elastomers. The chemical structures, LC properties and surface morphology of the monomers, the resins and the liquid crystalline elastomers (LCEs) are characterized by use of various experimental techniques such as FTIR, 1H NMR, EA, TGA, DSC, POM, and X-ray measurements. The mesomorphic properties of the synthesized resins and corresponding oriented elastomers are influenced by the terminal perfluorocarbon chains components effectively. The resins show chiral nematic and chiral smectic C phases (), and are frozen in their corresponding oriented elastomers. The LC phases are verified by X-ray measurements, and the orientational order parameters of the oriented LCEs are calculated as well. [Copyright &y& Elsevier]

Highlights: [•] Chiral liquid-crystalline elastomers were synthesized by hydrosilylation reaction. [•] The fluorinated chiral elastomers show chiral smectic C mesophase. [•] The fluorinated chiral elastomers display spontaneous polarization. [•] The glass transition temperature increases with increase of chiral crosslinking mesogens. [ABSTRACT FROM AUTHOR]