Wetting and anchoring of a nematic liquid crystal on a rough surface

Ellipsometric measurements of a nematic drop spreading on a rough surface are reported. The thickness profile of the drop shows two typical lengths belonging to the microscopic and to the mesoscopic scales (a few tens and some hundreds of Angstrom, respectively). No intermediate thicknesses are observed during the spreading. A simple model involving the balance among elastic, anchoring,and spreading energies is used to interpret the results.