Characterization of Polymer Interphases Using Surface-Enhanced Raman Scattering.

摘要

Surface-enhanced Raman scattering (SERS) and reflection-absorption infrared spectroscopy (RAIR) were used to determine the molecular structure of interphases between polymers and metal substrates. An interesting example was provided by pyromellitic diimide (PMDI), a model compound for polyimides, and silver substrates. Normal Raman spectra of PMDI were characterized by strong bands near 1772, 1370, 760, and 655 1/cm and medium intensity bands near 1630 and 1205 1/cm were weak in SERS spectra obtained from films of PMDI spin-coated onto silver island films while those near 1370 and 1205 1/cm and a new band near 685 1/cm were strongest. Differences between the normal Raman and SERS spectra were related to orientation effects indicating that PMDI was absorbed onto silver with a vertical conformation in which the rings were perpendicular to the surface and one imide group was in contact with the surface. Keywords: Polymer interphases, Surface enhanced raman scattering, Molecular structures, Thin films, RAIR, SERS, DD Form 1473, Spectroscopy. (JG)