From orthophosphate to phosphine-based groups: The effects of argon ion sputtering on doped polyethersulfone films

Pyridine-containing polyethersulfone films are being studied extensively as they are considered promising types of polymer electrolyte membranes to be used in high-temperature fuel cell (HT-PEMFC) applications. In this study, modified polyethersulfone films doped with phosphoric acid were bombarded by a 3 keV argon ion beam resulting in a different chemical environment at the end of the sputtering process. X ray Photoelectron spectroscopy (XPS) was employed to analyze the changes that occurred due to the exposure to the beam, confirming that distinct species appeared and indicating that reactions between the acid and the film occurred. These changes cause the formation of new phosphine-based structures and point out the impact of ions as a crucial factor in the degradation of doped polyethersulfone films.