Liquid-crystalline organic-inorganic hybrid polymers with functionalized silsesquioxanes

Liquid-crystalline (LC) hybrid polymers with functionalized silsesquioxanes with various proportions of LC monomer were synthesized by the reaction of polyhedral oligomeric silsesquioxane (POSS) macromonomer with methacrylate monomer having an LC moiety under common free-radical conditions. The obta ined LC hybrid polymers were soluble in common solvents such as tetrahydrof uran, toluene, and chloroform, and their structures were characterized with Fourier transform infrared, H-1 NMR, and Si-29 NMR. The thermal stability of the hybrid polymers was increased with an increasing ratio of POSS moiet ies as the inorganic part. Because of the steric hindrance caused by the bu lkiness of the POSS macromonomer, the number-average molecular weight of th e hybrid polymers gradually decreased as the molar percentage of POSS in th e feed increased. Their liquid crystallinities were very dependent on the P OSS segments of the hybrid polymers behaving as hard, compact components. T he hybrid polymer with 90 mol % LC moiety (Cube-LC90) showed liquid crystal linity, larger glass-transition temperatures, and better stability with res pect to the LC homopolymer. The results of differential scanning calorimetr y and optical polarizing microscopy showed that Cube-LC90 had a smectic-mes ophase-like fine-grained texture. (C) 2001 John Wiley & Sons, Inc.