A Mean-Field Photoreaction Model for the Pretilt Generation of a Liquid Crystal on Photopolymer Layers upon Ultraviolet Exposure

Abstract

We present a mean-field photoreaction model for the pretilt generation of a nematic liquid crystal (NLC) on the surfaces of photopolymers upon the exposure of ultraviolet (UV) light. The angular distribution function of photopolymer side chains, calculated in the photoreaction model, is used for determining the surface anchoring energy within the Rapini–Papoular approximation. The pretilt angle transition from the homeotropic alignment to the planar alignment of the NLC is demonstrated in two photopolymers with different alkyl chain lengths as a function of the UV exposure time. The main features of the experimental results agree well with theoretical predictions.

Colloidal particle-based surface nanotopography with high mechanical stability by thermal fixation for liquid crystal devices

“…The surface pretilt generated during the rubbing process is typically a few degrees depending on the nature of the alignment layer. 18 Thus, the symmetry-breaking effect by the surface pretilt is relatively small compared to that by the surface nanostructures. A HT LC cell and a TN LC cell assembled with the bottom substrate with the surface nanostructures and the top substrate without them are depicted in Figs.…”