PHOTOORIENTATION OF LIQUID CRYSTALLINE POLYMERS AND THE INFLUENCE OF AGGREGATION

摘要

The influence of molecular aggregation and liquid crystallinity on the photoorientation of azobenzene side groups is studied in a series of LC polyacrylates with different spacer length (x=2-10). In the case of polymers with long spacers the process is restricted by the aggregation, but the restriction can be overcome by a photochemical pretreatment irradiating with UV light or with Vis light of higher power density. After such a pro- cedure the optical anisotropy increases with the spacer length caused by the higher mobility and the higher ordering tendency of the polymers.