SCANNING TUNNELING MICROSCOPY AND ATOMIC FORCE MICROSCOPY CHARACTERIZATION OF POLYSTYRENE SPIN-COATED ONTO SILICON SURFACES

Scanning tunneling and atomic force images of polystyrene spin-coated onto silicon surfaces as a function of polymer molecular weight and concentration are presented. At low polymer concentrations (0.0005 wt %) individual polymer molecules are visualized; their apparent size increases with molecular weight. At concentrations above 0.05 wt % continuous films are seen. At intermediate concentrations, polymer molecules aggregate to form two-dimensional Voronoi tessellation-like networks. These are discussed in terms of a specific failure mechanism leading to film rupture in spin-coating processes.