Homogeneous Liquid Crystal Alignment by Polymerization of the Monomer Carrying Azobenzene Moiety in the Liquid Crystal

Abstract

The report introduces the fabrication method of a homogeneous liquid crystal (LC) alignment by exposure of a polarized ultraviolet (UV) above the nematic-isotropic transition temperature of the LC material (T_NI) to the cell including the mixture of the LC material and the monomer carrying an azobenzene moiety. First, the mixture of the LC material and the monomer was injected into the empty cell without forming a conventional alignment layer on substrates. The cellwas then exposed to polarized UV from the normal direction above the T_NI of the LC material. Finally, the homogeneous LC alignment was obtained, which shows the equal level of electro-optical and response properties of the conventional alignment layer on the substrates. The conventional fabrication process needed much amount of solvents and high temperature above 200℃ for forming the alignment layer, thus the proposed fabrication method would be significantly useful because it is expected to be eco-friendly.