SiO Evaporated Films Topography and Nematic Liquid Crystal Orientation

We present transmission electron microscopy micrographs of SiO films obliquely evaporated on indium-tin oxide coated glass surfaces. To study the growth mechanism of these SiO films, we present film cross sections in the evaporation plane. Varying the evaporation angle, we observe a column to needle transition, with increasing surface roughness. This transition corresponds to the planar to oblique nematic liquid crystal orientation transition, through the bistable one. The SiO surface roughness is estimated to induce a nematic surface order decrease (surface melting). The azimuthal nematic orientation on these plates corresponds to the direction of minimum surface melting. This confirms the predictions of the Barbero-Durand model.