Homogeneous liquid crystal orientation on ion beam exposure TiO2 surfaces depending on an anisotropic dipole field

Abstract

We studied homogeneous liquid crystal (LC) alignment properties on ion-beam (IB) irradiated TiO2 films deposited by the electron beam evaporation method. Stable homogeneous LC alignment on a TiO2 surface resulted from IB irradiation energy over 1800 eV. X-ray photoelectron spectroscopy analyses showed that Ti4+ 2p3/2 and Ti4+ 2p1/2 peaks were increased with increasing IB energy. Assuming that the increased peaks produced anisotropy dipole fields in the direction of the IB exposure process, we confirmed that the increasing IB energy induced strengthened the surface energy for entirely clear and stable LC molecule orientation. The voltage-transmittance characteristics of the twisted-nematic cell on the TiO2 surface indicate that the TiO2 film has potential for use as the LC alignment layer.