LIQUID-CRYSTAL MOLECULE ORIENTATION ON A POLYIMIDE SURFACE

Both bulk and surface characterization techniques (small angle X-ray diffraction (XRD), scanning tunneling microscopy (STM), and X-ray photoemission spectroscopy (XPS)) have been combined with theoretical calculations to investigate the chemical bonding characteristics of liquid crystal (LC) on polyimide. Both the morphology (as observed in XRD and STM) and the electronic structure (as observed by XPS) of the polyimide surface could be understood with the help of the results of self-consistent-field molecular orbital calculations. Changes that follow rubbing of the polyimide appear in each functional group of the polyimide unit cells parallel to the film surface, and the electronic states of the polyimide and the LC molecule give the LC orientation on the polyimide.