Surface modification of poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) with vacuum UV (VUV) photo-oxidation using radiation from excited Ar atoms downstream from an At microwave (MW) plasma shows: (1) an improvement in wettability as observed by water contact-angle measurements: (2) surface roughening; (3) incorporation of oxygen as C=O, CF-O-CF2 and CF2-O-CF2 moieties and (4) enhancement of the CF-O-CnF2n+1 concentration. Adhesion measurements of Cu sputter coated onto the photo-oxidized PFA surface results in failure within the PFA (cohesive failure) and not at the Cu-PFA interface.