Characterization of Model Polyimide/Silver Interphases Using Surface-EnhancedRaman Scattering

摘要

Surface-enhanced Raman scattering (SERS) was used to investigate the adsorptionof model compounds for polymides onto silver island films and onto highly oriented pyrolytic graphite (HOPG). SERS spectra of pyromellitic diimide (PMDI) adsorbed onto silver island films were mostly independent of the thickness of the PMDI films, confirming the SERS is an interfacial rather than bulk effect and that SERS can be used to examine the interface between an adsorbed film and a metal substrate without interference from normal Raman scattering by the bulk of the film. Differences in the relative intensities of several bands in the normal Raman and SERS spectra of PMDI adsorbed onto silver island films were related to orientation effects. It was concluded that most molecules were physisorbed with a vertical configuration in which the plane of the molecules was perpendicular to the surface and one imide group was adjacent to the surface. Keywords: Phthalimide(PIMH), Molecule structures, Organic chemistry, Adsorption, Surface properties. (JG)