PHOTOINDUCED OPTICAL ANISOTROPY IN LANGMUIR-BLODGETT-FILMS AS A NEW METHOD OF CREATING BISTABLE ANCHORING SURFACES FOR LIQUID-CRYSTAL ORIENTATION

We report a new method to prepare surfaces that creates two degenerate s states for liquid crystal orientation. The method uses Langmuir-Blod gett (LB) films exhibiting the effect of photoinduced optical anisotro py. We illuminate LB films twice with polarized light of perpendicular orientations to produce a special shape for the molecular distributio n function in a LB film. Nematic liquid crystal molecules (NLC) aligne d by these films can show two stable orientations, i.e. surface induce d bistability. The results observed are interpreted in terms of a micr o domain distribution in LB film. The origin of the bistability is ''e xtrinsic''.