Interfacial interactions of polymer coatings with oxide-free phosphate films on metal surfaces

Abstract

Thin oxide-free phosphate films of composition formed on the surface of vanadium metal and characterized by xray photoelectron spectroscopy A method for producing thin oxide-free phosphate films using an easier process than those previously reported is described. The process is carried out under ambient conditions using aqueous phosphoric acid. The chemistry of the phosphated surface prepared by the process and the interaction of this surface with a thin film of polyvinyl alcohol ͑PVA͒ are examined with the purpose of evaluating the potential of this film to serve as an adhesion promoting layer. The surface chemical changes are monitored by core and valence band x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy, with the resultant spectra compared to those from band structure calculations. Valance band photoemission interpreted by band structure calculations can be used to study the interfaces involved, and proves to be a very effective tool for conclusively identifying the surface species present. The process for forming oxide-free phosphate films forms the same surface chemistry as previously reported for other processes. PVA is found to strongly interact with the oxide-free phosphate film on aluminum metal illustrating the potential of such films as adhesion promoters.