SURFACE STUDY OF PLASMA-POLYMERIZED AND UV-POLYMERIZED STYRENE FILMS USING SCANNING FORCE MICROSCOPY AND IN-SITU PHOTOELECTRON-SPECTROSCOPY

Polymeric styrene films with thicknesses ranging from a few nanometres up to 3 mu m have been prepared by various techniques, such as UV polymerization, spin coating, d.c.- and r.f.-plasma deposition. These films have been characterized by in-situ photoelectron spectroscopy (PES) and scanning force microscopy (SFM) in order to study the electronic structure and the surface topography, respectively. The electronic structure of the films prepared by plasma- and photo-polymerization is very similar to the structure of conventionally synthesized polystyrene films. The plasma-polymerized films showed a surprisingly low roughness of <0.4 nm r.m.s. over a varied range of parameters and deposition techniques, i.e. r.f., d.c. anodic and d.c. cathodic plasma polymerization. Above 1 mu m film thickness, the roughness drastically increases up to about 2-3 nm. SFM measurements of spin-coated polystyrene films exhibited a surface topography and surface roughness similar to the plasma-polymerized films. A drastically different surface topography was found for the UV-polymerized styrene films. This difference in surface topography is discussed in detail together with the information obtained from the in-situ PES results.