Photoinduced orientation of liquid crystalline polymer film with N-benzylideneaniline containing side group

Abstract

Photoalignment is one of the most remarkable methods to induce a molecular orientation, based on axis-selective photoreaction. This technique is applicable to liquid crystalline (LC) display device, optical functional films, polarization diffraction device, etc. In general, photoinduced optical anisotropy is generated when a photoresponsive polymeric film is exposed to linearly polarized (LP) light. N-benzylideneaniline (NBA) derivatives undergo a trans-cis-trans photoisomerization similar to azobenzene derivatives with LPUV light exposure. Previously, we have found that liquid crystals polymer (LCP) with mesogens consisting of a Schiff base and phenyl benzoate exhibit large birefringence, and now we have synthesized LCPs with the Schiff base direction reversed (C=N→N=C) and examined their optical orientation.