Preparation of novel liquid crystalline polymeric film material and its photoinduced alignment behavior

Two kinds of novel oxetane monomers, containing biphenyl, flexible spacer and cinnamoyl group, were synthesized. The liquid crystal phase behavior of the corresponding polymers was investigated and isotropic-nematic, nematic-smectic and smectic-crystal transitions were identified during cooling. Both polymers exhibited clear fan texture morphology under a polarized optical microscope. Irradiation of a polymer film with linearly polarized UV light led to cycloaddition of the cinnamoyl groups, causing simultaneous alignment of the liquid crystal unit.