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By introducing two cholesteric liquid crystal monomers with different chain lengths (M1 and M2) and brominated naphthalimide fluorescent monomer (M3) into polymethyl hydrosiloxane, a series of fluorescent cholesteric liquid crystal polymers (FL-LCP) was prepared, which not only have excellent performance of liquid crystal and fluorescence but also own performance of selective reflection. Their chemical structures were confirmed to be in accord with molecular design by FT-IR and 1 H NMR spectroscopy, and found them with excellent thermal stability, mesomorphic behaviour and thermal performance by TGA, POM, DSC and XRD, and confirmed all the polymers belonged to the cholesteric phase. The FL-CLCPs emitted different intensity fluorescence under UV light, and conclusions about the relationship between fluorescence and temperature had been drawn. A comparative study was conducted on the fluorescence properties of powders and films of monomers and polymers. [ABSTRACT FROM AUTHOR]

In this paper, two series of side chain fluorescent cholesteric liquid crystal polymers (FL-ChLCPs) were prepared by one-step method with polymethyl-hydrosiloxane (PMHS) as the main chain. Two series of polymers differ in the structure of vinyl flexible chains of fluorescent monomer, the comparative study was conducted on their performance of liquid crystal and fluorescence. The compounds and polymers were characterised using conventional methods. The results indicated all polymers possessed dual optical properties of fluorescence and selective reflection, they also had excellent thermal stability. The FL-ChLCPs emitted different intensity fluorescence under UV light, the fluorescence intensity has a certain relationship with temperature and aggregation-caused quenching effect only occurs when the content of fluorescent monomer in the polymer exceeds 20%. [ABSTRACT FROM AUTHOR]

Two series of chiral liquid crystal compounds were synthesised from benzoic acid containing cholesterol with different carbon-chain lengths and bisphenol monoester containing camphoric acid with different carbon-chain lengths, named BCP-C and DCP-C. The structure of the monomers is characterised by IR, 1H NMR and 13C NMR, which indicate that the synthesised molecule conforms to the molecular design. The textures of monomers were characterised by POM, and their selective reflection was studied. It was found that the synthesised liquid crystal compounds exhibited good liquid crystal and optical properties. The phase transition behaviour was characterised using DSC, and the results were consistent with those observed by POM. TGA showed that they had good thermal stability. [ABSTRACT FROM AUTHOR]

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, we have synthesised fluorescent liquid crystal polymers with good fluorescence and optical properties through effective molecular design. Firstly, two series of cholesteric liquid crystal polymers (PN and PS series) were prepared by graft copolymerisation of cholesteric monomer(N1), monomer containing cyanobiphenyls with different length of carbon-chain (N2 and N3) and monomer containing bromine (6-Br) with polymethylhydrosiloxane chain as the polymer backbone. Secondly, we obtained fluorescent polymers RPN and RPS series by etherification reaction of PN and PS series with fluorescent monomer (F). The molecular structures and mesomorphic behaviour of monomers and polymers were characterised by usual ways. All the polymers are confirmed to consist with molecular design. The fluorescence of the polymers was investigated by fluorescence spectroscopy and fluorescent images. The fluorescence intensity of polymers is highly dependent on temperature. Fluorescent cholesteric liquid crystal polymers emitted different intensity fluorescence under ultraviolet irradiation and some regularities were summarised. RPN series with short carbon-chain meets our expectations for performance with dual effects of fluorescence and selective reflection, which were well verified. The effect of monomers with different chain lengths on the properties of fluorescent polymers has been described. Fluorescent cholesteric liquid crystal polymers were synthesised with polymethylhydrogensiloxane as the main chain by hydrosilylation and etherification reaction, which seems a viable strategy for preparing such multifunction polymers. The polymers of RPN series we synthesised are equipped with both selective reflection and fluorescence properties. The selective reflection and fluorescence both have a characteristic of depending on temperature. The fluorescent cholesteric liquid crystal polymers we synthesised presented lower glass transition temperature and higher isotropic transition temperature. In other words, it has a wide range of application. [ABSTRACT FROM AUTHOR]

In this paper, two series of cholesteric liquid crystal polysiloxanes (PA and PB series) with selective reflection were synthesised. PA and PB series were both prepared by hydrosylation of monomer MA containing cholesterol, monomer MB containing D (+)-camphoric acid and 6-bromohexene (6-Br), besides PB series containing MC with cyano-group. The optical performance and thermal stability of PA and PB were observed, and the relationship between PB series and PA series was also studied. Tests such as POM, TGA, DSC and selective reflection showed that the polymers exhibited colourful Grandjean texture and excellent thermal stability. The Tg, Ti and the mesophase temperature for the PA series all tended to increase, and with the increase of steric hindrance of MB, the selective reflection may exhibit more difficulty. The PB series could dilute the steric hindrance of chiral monomers due to the introduction of cyano-group and the decrease content of MB, which not only guaranteed the polymer with wider mesophase temperature but also was conducive to appear the selective reflection and last longer, besides, with the temperature increased, the wavelength of the reflected light intended to blue shift compared to that of PA series with the same chiral contents. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals with selective reflection have important applications in the field of light control and optical thin films. In this study, a series of side-chain cholesteric liquid-crystal polymers (named as PPL series) was synthesised by a one-step hydrosilylation reaction among monomer LA containing cholesterol group, monomer LB containing D(+)-camphoric acid group and monomer LG containing cyano group. The chemical structures and the mesogenic properties of the monomers and polymers were determined by usual test methods. Testing results showed that PPL series polymers had excellent thermal stability and wide range of mesophases. As the content of monomer LB increased, PPL1-PPL6 could be observed colourful Grandjean textures and good selective reflection. The optical rotation experiment indicated that the rotation direction of the PPL series was consistent with that of the monomer LB, and the specific rotation was linearly related to the content of the monomer LB. [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]

In this study, we synthesised two series of cholesteric liquid crystal polymers CPQ and CPZ series. First, we prepared four different monomers ML1 containing a cholesteryl group, ML2 containing a cyano group, ML3 containing a phenolic hydroxyl group and ML4 containing isosorbide with azo groups. With the polymethylsiloxanes as the main chain, CPQ series were then synthesised by copolymerisation among the monomers ML1, ML2 and ML3 and CPZ series were synthesised by esterification between the CPQ series and the monomer ML4. 1HNMR and FT-IR spectra confirmed the chemical structures of all the monomers and polymers. The mesomorphic behaviours and thermal properties were investigated by TGA, DSC, POM and XRD. Both the CPQ and CPZ series exhibited excellent thermal stability and reversible phase transitions, as well as interesting Grandjean textures under POM. CPZ series showed higher optical activity than CPQ series due to the introduction of the isosorbide group and the azo group, which could tune the pitch to make Bragg selective reflection appear more easily. UV–Vis spectra investigated the photoresponse behaviours of CPZ series thoroughly. [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]

In this study, we designed, synthesised and characterised two series of cholesteric liquid crystal polymers, QP series and ZP series. With polymethylhydrosiloxane as the main chain, QP series were synthesised by copolymerisation between the monomer M1 containing a cholesteryl mesogenic unit and the monomer M2 with a hydroxyl. ZP series, meanwhile, were synthesised by esterification between QP series members and the monomer M3, a carboxylic acid with an azo mesogenic unit. We characterised chemical structures of all the monomers and polymers by FT-IR and 1H-NMR, which proved that the target monomers and polymers had been obtained. We observed dramatic colour changes after the introduction of monomer M3 and Grandjean textures from both QP series and ZP series using POM. In addition, strong selective reflection could be observed as well. Then, we characterised the thermal properties of polymers by DSC, TGA and XRD to explore their phase transition behaviours further. Their photoresponsive and photochromic properties were characterised by UV-Vis spectrum. [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 two-arm ( MA1 , MA2 ), four-arm ( MA3 ) and six-arm ( MA4 ) chiral liquid crystalline compounds containing isosorbide as the chiral core were synthesised. Four precursors of branched-arm A1–A4 were first obtained, and then were esterised separately with isosorbide to obtain four chiral branched-arm liquid crystals ( MA1–MA4 ). The structure and properties have been characterised. The results show that MA1 was smectic–cholesteric phase with a fan-like and oily streak texture; MA2–MA4 showed a cholesteric phase with oily streak texture, or lined texture and finger print texture. Isosorbide successfully induced a cholesteric phase. The melting point and clearing point values for MA1–MA4 first increased and then decreased. The branched-arm and chiral core quantity affected the liquid crystalline properties. At the same time, the difference in side-arms resulted in different directions of rotation. MA1–MA2 showed right-handed rotation and had selective reflection; MA3–MA4 demonstrated left-handed rotation and did not have selective reflection. [ABSTRACT FROM AUTHOR]