INVESTIGATING POLY(1-BUTENE) FILMS BY SFM STM

Ultrathin poly(1-butene) (PB-1) films drawn from the melt have been deposited on substrates of highly oriented pyrolytic graphite (HOPG) for an investigation using both a scanning tunneling microscope (STM) and a scanning force microscope (SFM). The aim of the investigation was to study the surface electronic and topographic structure of these ultrathin polymer films which strongly determine the interfacial properties in contact with other materials, as for example in composite materials. In addition, metal decoration of the polymeric substrates allows investigation of the assumed grapho-epitaxial growth processes on polymers. The results obtained from SFM measurements show the needle-like structure of the uniaxially stretched polymer as well as cracks in the thin organic film. On continuous film sheets the film topography was found to consist of PB-1 fibrils with loose dangling ends. These SFM images, which excellently agree with previously reported transmission electron microscopic (TEM) investigations, are compared with those obtained on metal-decorated PB-1 film surfaces. Close to monomolecular areas of the PB-1 film, high-resolution STM imaging simultaneously reveals the atomically resolved HOPG substrate surface as well as a helical structure originating from the polymer film. STM results obtained on the PB-1 films are compared with recent measurements on poly(ethylene) (PE).