Optically Controlled Alignment of Nematic Liquid Crystals on Photo-sensitive Polymers

Alignment properties of nematic liquid crystals (LC) on photo-exposed polymer films have been investigated. Polyimide films prepared from cyclobutane tetracarboxylic dianhydride (CBDA) induced an excellent uniform LC alignment by exposure of linearly polarized UV light. The sensitivity of the photo-alignment of CBDA polyimide films was higher than that of aromatic polyimide films. On the other hand, the LC alignment on fully aromatic polyamide films exhibited the excellent uniformity, although these polyamides contained no photo-reactive groups such as cinnamoyl group. The obtained LC alignment was thermally and optically stable.