Photoalignment of liquid crystals on photo-cross-linkable polymer liquid crystal with coumarin containing side group

Abstract

Photo-cross-linkable polymethacrylate comprising a coumarinmethylbiphenyl side group was synthesized. A linearly polarized ultraviolet (LP-UV) light irradiated the synthesized polymer films, and the resultant films were applied to the alignment layer for liquid crystals (LCs). The optical anisotropy was induced by LP-UV light irradiation and the positive dichroism was generated when the film was exposed near clearing temperature of the film. The LC could be aligned on the exposed films and the alignment direction was controlled by adjusting the irradiation condition. The photo-cross-linked mesogenic side groups determine the LC alignment direction.