Mechanically and light induced anchoring of liquid crystal on polyimide film

The interplay between the effects of mechanical rubbing and UV light induce d deimidization on polyimide films has been studied. Exposure to depolarize d UV light of rubbing PI film was found to suppress effective anchoring ene rgy. Polarized light led to the alteration of the orientational distributio n of PI molecules obtained by rubbing i.e to the change of both anchoring e nergy and easy axis direction. A simple model based on the selective UV lig ht absorption with consequent deimidization of PI molecules describes the U V-initiated processes on the rubbed polyimide layers but contradicts the ex perimental data obtained for non-rubbed layers. The results obtained show t hat UV exposure can be effectively used to control anchoring parameters.