Surface alignment of ferroelectric liquid crystals using polyimide, polyamide-imide and polyamide layers and their effect on pre-tilt angle

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Abstract
Fluoro and non-fluoro polymer alignment layers of high and low pre-tilt angle were developed for ferroelectric liquid crystal display devices to exploit the effect of rubbed polyimide, polyamide-imide and polyamide alignment layers on pre-tilt angle and other electro-optical properties. Fluorine containing polyimide and polyamide alignment control layers displayed high pre-tilt angle (< 10°) and good alignment of liquid crystal molecules with no zig-zag defects by means of standard rubbing techniques. Non-fluoro polymer alignment layers showed relatively small pre-tilt angle (< 5°) with good or random alignment having some zig-zag defects in the ferroelectric liquid crystal cells. The ferroelectric liquid crystal used in the experiment was CS-1011 having the phase sequences SC*-SA-N*-I. The characteristic changes due to structurally different polymer layers on ferroelectric liquid crystal alignment are described.