Vertically aligned liquid crystal molecules on TiO₂ film treated by ion-beam irradiation

In this paper, we describe the formation of vertically aligned liquid crystal molecules on TiO₂ films treated by ion-beam (IB) irradiation. Regular or irregular pretilt angles were achieved as a function of IB incident angle. Uniform alignment was obtained only at an incident angle of 45°. The contact angle, which is related to the surface energy, was measured to confirm the tendency of variation in the pretilt angle. In addition, the weak anchoring energy of LC molecules on IB-irradiated TiO₂ was ascertained by the thermal stability at low temperature.