Using fast atomic source and low-energy plasma ions for polymer surface modification

A systematic study was carried out to characterize the effects of argon atomic beam irradiation and low-energy argon ions in plasma for polystyrene (PS) surface modification. The PS samples were exposed to a 1.5 keV, argon atomic beam from a fast atomic source (FAS) at different exposure times. The low-energy (1.5 eV) argon plasma ions were achieved in a two-stage RF discharge and PS samples were exposed to plasma for different times and powers. The surface characterization of these atomic beam and plasma modified PS samples was carried out using X-ray photoelectron spectroscopy. For FAS, the results showed a rapid increase (from 0.01 to 0.18) in oxygen-to-carbon ratio (O/C) at the surface of PS with first 10 s exposure time while further increase in exposure time up to 500 s showed about 50% decrease in O/C. Therefore, first few seconds of atomic beam irradiation useful to increase the O/C at the PS surface whereas at higher irradiation time the surface etching may took places and it could have advantage in surface cleaning. A comparison of O/C with FAS and plasma ions showed FAS is more effective way to achieve oxygen incorporation at PS surface relatively to low-energy flux plasma ions.