Characterization and alignment properties of rough substrates

We have determined by atomic force microscopy the average roughness of subs trates covered with a different indium tin oxide (ITO) thickness. We have f ound that the higher the ITO thickness is the higher the roughness. Then, t he preferential alignment of liquid crystalline mixtures, formed by a low m olecular weight liquid crystal and a liquid crystalline monomer, on such su bstrates has been investigated, Samples have turned out to be homeotropical ly aligned by surface interactions. These cells have been UV irradiated in order to achieve the photo-polymerization of the liquid crystalline monomer . We have found that rougher surfaces are able to store the homeotropic ali gnment in the anisotropic polymer matrix. The order degree of polymerized f ilms has been estimated as a function of liquid crystal content.