Cholesteric Cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes

Abstract

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.