Polystyrene Derivative Films for Liquid Crystal Alignment

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Abstract
We studied the alignment of liquid crystal molecules on rubbed, thin polymer films of polystrene and its derivatives. Liquid crystal molecules were aligned perpendicular to the rubbing direction, although the polymer main chains of rubbed films were oriented along the rubbing direction. The alignment of the liquid crystal depended on the choice of side phenyl groups of polystyrene derivatives, and the pretilt angle varied with the type and the position of the substituents that were introduced into the side phenyl groups. Homogeneous alignment for ferroelectric liquid crystal was obtained by using poly(NO2 styrene), poly(p-OH styrene) and poly(4-vinylpyridine) films, which have relatively high β-dispersion and glass transition temperatures.