Synthesis and Characterization of a Liquid Crystalline Polyferrocenylsilane Brush

A grafted side chain liquid crystalline polymer brush with poly(ferrocenylsilane) as the main chain and poly{6-(4'-butyloxyphenyl 4 ''-benzoyl)hexyl acrylate} as side chain has been synthesized by atom transfer radical polymerization (ATRP) technique. For comparison, a linear liquid crystalline polymer, poly{6-(4'-butyloxyphenyl-4'-benzoyl)hexyl acrylate}, was prepared by conventional radical polymerization method. Both of them were characterized by NMR, FT-IR, GPC and TGA. Their liquid crystalline properties have been investigated by means of differential scanning calorimetry, polarizing mciroscope and X-ray scattering. The liquid crystal phase behavior research demonstrated that both of them were reversible thermotropic nematic phase in the high temperature region and smectic A phase in the low temperature region. In comparison with linear liquid crystalline polymer, liquid crystalline polyferrocenylsilane brush exhibited the lower glass transition temperature (T-g) and clearing point (T-NI). Results showed that the brush architecture made the alignment of the mesogens more difficult than those in its monomer and linear polymer.