CONTINUITY OF VERY THIN POLYMER-FILMS

Thin films (0.5-100 nm) of natural rubber, polystyrene, and poly(methyl methacrylate) were deposited on silicon wafer a by spin-casting from dilute solution. The average thickness of the layers was determined by ellipsometry. Contact angle measurements, along with atomic force microscopy, were used to investigate the homogeneity of the layers. The critical average film thickness e, required to completely cover the surface differed greatly (between 1.6 and 30 nm), depending on the surface treatment of the wafers and the polymer used.