Treatment of poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) with vacuum ultraviolet (VUV) radiation from high pressures of helium in rotating dc arc plasmas was investigated. X-ray photoelectron spectroscopy (XPS) detected defluorination and appearance of the functional groups (C=O, O-C=O and C-O) on the surface. Fourier transform infrared (FT-IR) spectroscopy showed the appearance of a band at 1884 cm(-1) indicating the formation of the carboxylic acid fluoride moiety, -(C=O)-F. Improvement in film wettability was observed by contact angle measurements while SEM micrographs showed an increased amount of cracking on the surface with VUV exposure. Adhesion measurements of Cu sputter-coated onto the photo-modified surfaces resulted in failure within the fluoropolymer (cohesive failure) and not at the Cu-fluoropolymer interface. Cohesive failure occurred with shorter treatment times than for VUV exposure downstream from low pressure Ar microwave plasmas.
Department, Program, or Center
School of Physics and Astronomy (COS)
Journal of Adhesion Science and Technology 21 (2007) 983-998
RIT – Main Campus