Photoinduced alignment behavior of polymer liquid crystals containing azobenzene moieties in the side chain

Abstract

Azobenzene-containing polymeric systems are being developed as materials for photonic applications. The present work deals with the photoinduced two-dimensional (2-D) and three-dimensional (3-D) alignment behavior of polymer liquid crystals (PLCs) with azobenzene moieties in the side chain. 2-D alignment of the PLCs was brought about on irradiation of linearly polarized light. The effects of various factors such as experimental conditions and structural parameters of the PLCs on the 2-D alignment behavior have been explored in detail. The response was enhanced by two methods: chemically tailoring structure of the PLCs and physically modifying the alignment procedure. 3-D alignment of the azobenzene moieties was achieved on irradiation of unpolarized light. It was revealed that the azobenzene moieties were aligned along the propagation direction of the irradiation light. Inert mesogens underwent reorientation together with azobenzene moieties in the 2-D as well as 3-D alignment process. © 1999 IUPAC.