Photoinduced Deformation Behavior of Crosslinked Azobenzene Liquid-Crystalline Polymer Films with Unimorph and Bimorph Structure

The use of a crosslinked azobenzene liquid-crystalline polymer (CALP) system for micro-integrated actuators becomes especially attractive. CALPs can deform along the alignment direction of mesogens upon irradiation of UV/visible light owing to photochemical phase transition. In this study, to improve the bending speed, CALP films with a homogenous alignment on one surface and a homeotropic alignment on the opposite surface (hybrid alignment) were prepared and their bending behavior was investigated. The films showed photoinduced bending whose direction was determined by the surface alignment treatment, and the bending speed was greatly enhanced upon irradiation from both surfaces of the film at the same time.