The high pretilt alignments of thin layer of discotic liquid crystals, triphenylene benzoates with acryloyl group at each end of radial side chain are generally observed. By examining the possibility of pretilt angle control of discotic compounds, we have achieved homeotropic alignment of them with a certain kind of additives. Homeotropic alignment was confirmed by elipsometric measurement of thin film retardation and polarized microscopic observation of ultra thin cross-sectional images of molecular orientation. This novel alignment was found to achieve without any rubbing treatments of substrate.
