Synthesis and mesomorphic properties of a novel ladder-like 1,4-phenylene-bridged liquid crystalline polysiloxane containing ester-based mesogenic side groups

A new ladder-like 1,4-phenylene-bridged liquid crystalline polysiloxane bea ring ester-based mesogenic side groups, LPLCPS, has been synthesized by hyd rosilylation of a SiH-terminated ester-based mesogen compound (1) with a la dder-like 1,4-phenylene-bridged polyvinylsiloxane (LPPVS) containing vinyl- terminated side groups in the presence of dicyclopentadienylplatinum(II) ch loride (Cp2PtCl2) catalyst. Compound 1 was synthesized by hydrosilylation o f 1,1,3,3-tetramethyldisiloxane (HMM) with the vinyl-terminated ester-based mesogenic compounds. Various characterization methods including FTIR, H-1 NMR, C-13 NMR, Si-29 NMR, polarizing optical microscopy, differential scann ing calorimetry and X-ray diffraction were used and the results combined to demonstrate that LPLCPS shows thermotropic smectic mesomorphic behaviour w ith a high clearing point and a wide mesophase range.