Anchoring structure of liquid-crystal monolayers on polyimide Langmuir-Blodgett films observed by scanning tunneling microscopy

Using scanning tunneling microscopy, we directly observe monolayers of smectic liquid crystal, 4'-n-octyl-4-cyanophenyl (8CB), on oriented polyimide Langmuir-Blodgett (LB) films. We find that the monolayers form a two-dimensional crystalline structure and 8CB molecules are always aligned along the chain direction of polyimide. The results demonstrate that the anchoring structure of 8CB monolayers is an epitaxial alignment growth on the oriented polyimide LB films.