Metal–polymer chemistry. II. Chromium–polyimide interface reactions and related organometallic chemistry

We have studied the reactions occurring for the deposition of chromium onto pyromellitic dianhydride-4,4′-oxydianiline (PMDA-ODA) polyimide for a wide range of metal coverages, using x-ray photoelectron spectroscopy as well as solution studies of model compounds. A multistep, coverage-dependent mechanism is proposed which includes an initial electron transfer from Cr to PMDA-ODA, followed by formation of Cr–O and Cr–N polymer-bound intermediates. At higher metal coverage, Cr–oxides and Cr–nitrides are formed which may activate the polymer for subsequent formation of Cr–carbide. In the course of this work we have shown that similarities exist between the chemistry of metal atoms in condensed phases and the reactions occurring between metal atoms and surfaces.