Observation of the Surface Structure on As Stacked and Rubbed Polyimide(PI)-LB Films with an Atomic Force Microscope and Their Anchoring Capability for Nematic Liquid Crystal

We have observed the surface structure of stacked and rubbed polyimide(PI)-Langmuir-Blodgett(LB) films with an atomic force microscope. It is shown that no grooves are formed on the PI-LB films stacked on ITO coated glass plates for a range of rubbing strengths; instead, the surfaces are rather flattened by the rubbing. We have measured the polar anchoring energies for nematic liquid crystals (NLC), 5CB oriented on these films and it is shown that they increase with the rubbing strength. Furthermore, textures of the aligned phase of the NLC have been examined. The textures are shown to become more uniform due to the rubbing.