Photocontrol of Liquid Crystal with p-Cyanoazobenzene Polymer Thin Films

Abstract

In-plane alignment control of liquid crystals (LCs) is achieved by linearly-polarized-light (LPL)-treated thin film of polymers having azobenzene side chains. Thin films of p-cyanoazobenzene polymer were irradiated with LPL and absorption dichroism was observed. The dichroic ratio of the polymer thin film was enhanced by heating at 240℃ above Tg of the polymer. The LC alignment on the polymer film was maintained after heating at 100℃ for 1 hour. The thermal stability of LC alignment reflects the stability of dichroism of the polymer film.