Effect of Substrate Surface on Alignment of Liquid Crystal Molecules

Investigations were made of tilt angles of the molecular long axis in a liquid crystal layer sandwiched between two substrates, which were prepared by evaporating silicon at oblique incidence. Measurements of the dependence on the incident angle were carried out, which showed that the tilt angles varied from 3° to 28.4° for the incident angles ranging from 67° to 86°. Observations of the deposited film surfaces by use of electron microscopy revealed that they had a sawtooth-like structure whose shape also depended on the incident angle. It was suggested that the tilt angle was strongly affected by surface structures of the substrates.