Cholesteric Cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes

Abstract:

Two new kinds of Cholesteric cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes (P_A and P_B) were synthesized via hydrosilylation reaction of polymethyl hydrogen siloxane with cyclohexane mesogenic monomers (M_A and M_B). The yield of P_A, P_B were 71.6%, 82.5% and 81.0%, respectively. The molecular structures of M_A and M_B, P_A and P_B were 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 M_A and M_B exhibited multicolor platelet texture of a blue phase and cholesteric phase, and the T_m and T_i of M_A and M_B increased with the increasing flexible chain length. The mesophase temperature range of P_A and P_B was broader than that of M_A and M_B. P_A exhibited a rare nematic phase----spherulite texture of polymeric smectic A phase. P_B were of cholesteric and nematic---- cholesteric phase. The T_m and T_i of P_A and P_B increased with the increasing flexible spacer groups.

• Periodical: Materials Science Forum (Volumes 809-810)
• Pages: 308-312
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.809-810.308
• Online since: December 2014
• Authors: Ying Li*, Liang Zhang, Meng Jie Chang
• Keywords: Cholesteric Phase, Liquid Crystalline Polymer, Polysiloxanes, Smectic A Phase

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