Adhesion of copper to poly(tetrafluoroethylene) and fluorinated ethylene propylene copolymer surfaces modified with vacuum UV radiation from helium arc plasma

Teflon materials including poly(tetrafluoroethylene) (PTFE) and poly (tetrafluoroethylene-co-hexafluoropropylene) (FEP) were exposed to vacuum UV (VUV) radiation from a He DC arc plasma that was made to rotate inside of a graphite tube by the application of an auxiliary magnetic field. The polymer films were covered with optical filters having different cut-off wavelengths to vary the spectrum of the VUV radiation that modified the fluoropolymer surface. The properties of the surface changed after surface modification as follows: (1) water contact angles started to decrease in the wavelength region between 173 and 160 nm and continued to decrease with shorter wavelengths; (2) surface roughening; (3) defluorination of the surface with a slight increase in the atomic %C and formation of C-C bonds in the top 3-5 nm of the surface as detected by XPS analysis; and (4) incorporation of oxygen upon exposure to air. Changes in the adhesion of copper to these modified surfaces were observed