Surface modification of the polyimide films by electrical discharges in water

Pulsed electrical discharges in distilled water were used for the surface modifications of the aromatic polyimides. Optical emission spectroscopy has shown the formation of excited species in the plasma due to water dissociation and ionization. The reactive species have induced surface modifications of the polymer films which were investigated by FTIR, AFM, XPS, and static contact angle measurements. The surface hydrophobicity of the polyimide films increased with the plasma treatment time due to the segregation of the CF₃ groups at the polymer surface and the imidization of the polyimides during the plasma discharge. Pulsed electrical discharges generated in distilled water are used to modify the surface of the aromatic polyimide films. The reactive species formed in the water plasma have induced surface modifications of the polymer. FTIR, XPS, and static contact angle measurements have confirmed the increased surface hydrophobicity of the water plasma treated polyimide films.