UV-driven in-plane rotation of a liquid crystal director in poly(vinyl cinnamate) films having microscale grooves

Abstract

The micropatterned poly(vinyl cinnamate) (PVCi) alignment layers are fabricated by a solvent-assisted micromolding method. Without UV irradiation, the alignment layer can induce the unidirectional liquid crystal (LC) orientation, which is influenced by topography-based anchoring energies. With photodimerization of PVCi by UV irradiation, we could modulate the anchoring energies caused by chemical interactions of the alignment layer. It is observed that these two different contributions compete against each other in determining LC rotation on the surface of the alignment layer. The rotation angle of LC directors could be controlled from 45 to 70 by simply changing the UV exposure dose. (C) 2010 Optical Society of America