Fabrication of liquid-crystalline polymer films with cycloidal molecular alignment patterns by scanning wave photopolymerization

Abstract

The control of molecular alignment patterns in liquid crystals is key to developing high-performance optical devices. In particular, two-dimensionally designed patterns have attracted much attention due to their potential application to novel optical devices such as a high efficiency polarization grating and a vortex converter. However, there remain challenges in obtaining molecular alignment patterns by a simple method. We have recently proposed a novel method for controlling the alignment of liquid crystals termed scanning wave photopolymerization (SWaP). In this method, a mass flow triggered by spatiotemporal photopolymerization causes shear stresses to anisotropic molecules, resulting in the generation of alignment patterns finely guided by the scanned light. In this study, we present the direct fabrication of polymer films with cycloidal molecular alignment patterns by SWaP.