Effect of Urethane Acrylate Oligomer and UV Curing Temperature on Electro-Optical Property of Polymer-Dispersed Liquid Crystal

Abstract

Polymer-dispersed liquid crystal (PDLC) films were prepared by photopolymerization after substituting the reactive diluent monomer 2-ethylhexyl acrylate with an aliphatic urethane acrylate (UA) oligomer in a conventional pre-polymer (PN393). The effects of UA concentration and UV curing temperature on the PDLC films' physical properties were examined. The average LC droplet size decreased with increasing UA concentration. The driving voltage decreased by 30% and the response time increased by 26%. The PDLC films with 30 wt% of UA showed the lowest driving voltage and the highest contrast ratio when the LC pre-polymer mixture was UV-cured slightly above the nematic-isotropic coexistence temperature. © Taylor & Francis Group, LLC.