Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.338, 35-46, 2000
Photoalignment of low-molecular liquid crystals on photo-crosslinkable copolymer liquid crystalline film comprising photoreactive and photoinactive side groups
We present photoalignment behaviors of low-molecular liquid crystals (LMLCs) on a photo-crosslinkable side-chain copolymer liquid crystal (CPLC) containing a 4-(2-cinnamoyloxyethoxy)biphenyl group and a 4-cyanobiphenyl group by use of linearly polarized (LP) UV irradiation. The LMLC aligned homeotropically on the photoreacted film in the initial state of the photoreaction and the alignment direction changed homogeneously on further irradiation. The direction of the homogeneous alignment can be controlled to be parallel or perpendicular to the electric vector of the LP-UV light, by changing the irradiation temperature or the degree of the photoreaction. These alignment behaviors are explained by the interaction between the LMLCs and the photoreacted CPLC film.