CHEMICAL MODIFICATION OF POLYSTYRENE SURFACES BY LOW-ENERGY POLYATOMIC ION-BEAMS

The chemical modification of polystyrene surfaces by low-energy (10-10 0 eV) SF5+, C3F5+, and SO3+ ions was studied by X-ray photoelectron sp ectroscopy and two-laser ion trap mass spectrometry. The mechanism of fluorination was found to be dissimilar for SF5+ and C3F5+ ions in thi s energy range at fluences of 10(14)-10(16) ions/cm(2). SF5+ was found to induce fluorination of the polymer surface by grafting reactive F atoms upon dissociation at impact. SFn fragments were not found to be grafted or implanted into the polymer. Sulfur was detected on the poly mer surface only at incident energies above 50 eV and was found to be sulfidic in nature. In contrast, C3F5+ ions induced grafting of both r eactive F atoms and molecular CmFn fragments from the dissociation of the incident projectile. Larger proportions of highly fluorinated site s and thicker fluorocarbon layers were found for C3F5+ at all energies and fluences. A variety of aliphatic and aromatic fluorine bonding en vironments were detected on both SF5+ and C3F5+ modified polystyrene s urfaces.