Molecular orientation of new photosensitive polyesters for liquid crystal alignment

Abstract

New polyesters with the main-chain cinnamoyl group, but with the different length of alkyl side-chain have been investigated their photoreactivity and photoalignment characteristics using UV-VIS absorption and FTIR spectra. In the case of Cn-polyesters, chromophores in cinnamoyl group are found to involve in the (2 + 2) cycloaddition reaction. The remained chromophores demonstrate a preferred orientation in the direction perpendicular to the exposure direction of the linearly polarized UV light, whereas photodimers do not display any anisotropy. (C) 2002 Elsevier Science B.V. All rights reserved.