ABSTRACT
This chapter aims to study the alignment properties of polyimide Langmuir-Blodgett (LB) films on nematic liquid crystal (LC) in order to evaluate the potential of LB film for uses in real applications and to understand the mechanisms responsible for the LC alignment. Most of the liquid crystal displays produced today are either twisted nematic or supertwisted nematic electrooptical effects. The molecular orientation in the LB films prior to and after imidization was also qualitatively evaluated by comparing the relative peak intensities of the Fourier Transform Infrared Spectroscopy transmission spectrum with those of the reflection-absorption spectrum for the same film. The chapter suggests that the polyimide LB films were unable to provide pretilt angles due to the fact that the polymer backbones tend to be parallel to the surface substrate, as was shown by the IR and atomic force microscopy results. Polyimides are quite insoluble in organic solvents, and the only hydrophilic groups are the carbonyl groups in the polymer backbone.
