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A study on nitrogen plasma functionalization of polyethyleneterephthalate (PET) is presented. Samples were exposed to a weakly ionized, highly dissociated RF nitrogen plasma with an electron temperature of 5 eV, a density of positive ions of the order of 1015 m-3 and a density of neutral nitrogen atoms of the order of 1021 m-3. The nitrogen pressure was 75 Pa and a discharge power was 200 W. The samples of PET foil were exposed to plasma and its afterglow from 3 s to 10 s. After plasma treatment the surface was analysed by XPS (X-ray photoelectron spectroscopy) and AFM (Atomic Force Microscopy). XPS results showed that already in three seconds of the plasma treatment the surface was covered by new functional groups. The surface roughness was increase as shown by AFM. The wettability of the plasma-modified PET surface as well as stability of the functional groups on the plasma-modified PET surface was determined by measuring the contact angle of a water drop. |