INVESTIGATION OF THE INTERFACIAL ORDER OF NEMATIC LIQUID-CRYSTAL ON PHOTOPOLYMER COATED CONDUCTING GLASS SUBSTRATES WITH A SCANNING TUNNELING MICROSCOPE

High resolution images of individual molecules of the liquid crystalli ne material adsorbed on a photopolymer treated transparent conducting (indium oxide coated) glass plate have been obtained with a scanning t unneling microscope (STM). The ultrathin layer of the photopolymer pol y-vinyl-4-methoxy-cinnamate (PVMC) on the conducting glass plate was d eposited by the bulk induced alignment technique reported earlier [S. C. Jain and H.-S. Kitzerow, Appl. Phys. Lett. 64, 2946 (1994)]. The li quid crystal molecules exhibit a positional order, in addition to a hi gh degree of orientational order of the bulk nematic. This surface ord ering of the nematic liquid crystal at the polymer interface is quite different from the ordering observed on graphite and molybdenum disulp hide substrates. A small ensemble of molecules show antiparallel order ing of the cyano-phenyl-cyclo-hexane molecules in agreement with the c alculations of Schadt et al. [Liq. Cryst. 5, 293 (1989)]. (C) 1995 Ame rican Institute of Physics.