Anisotropic photo-polymerization and fluorescence study of discotic materials

The discotic films were prepared by coating the solution of liquid crystall ine discotic monomer and initiator onto rubbed polyimide as alignment subst rate. Liquid crystalline orientation in films was freezed-in by photo-polym erization (UV light) in nematic melt. Thickness and chemical constituents o f polyimide was varied so as to obtain planar or homeotropic alignment. Pho to-polymerization was studied with respect to isothermal DSC, PM, high temp erature IR and solubility behavior of polymerized films. Further, the align ment of discotic films was studied by polarized fluorescence. Order paramet er values were compared for planar, homeotropic and for films without any a lignment substrate. Higher values were obtained for planar films formed on polyimide layer than formed solely on glass surface.