Improving Liquid Crystal Alignment Ability and UV Sensitivity in Photodecomposition Polyimide Film

Abstract

A liquid crystal alignment film with fewer processes capable of imparting anisotropy was developed using a polyimide, which utilized the cleavage of a cyclobutane ring by irradiation of polarized UV light at 254 nm. When an aromatic diamine with alkylene in the molecular center was used, an even methylene number of diamines showed superior liquid crystal alignment ability compared with diamines with an odd methylene number. Additionally, a diamine containing a molecular structure with a pre-imidized imide group adjoined to a cyclobutane ring was extremely effective in improving liquid crystal alignment ability and sensitivity to polarized UV light.