Surface modification of thin polymeric films by air-plasma or UV-irradiation

Commercial, purified poly(vinyl chloride) (PVC) in a form of thin film was used for modification by low-temperature air-plasma or short-wavelength UV-irradiation. The changes of surface properties were monitored by contact angle measurements allowing for calculation the surface free energy as well as its polar and dispersive components. Both modification sources cause surface oxidation of PVC films, which is connected with formation of functional groups enhancing polymer wettability. This process is very fast and efficient in air-plasma but slower during PVC exposure to UV. Storage of modified PVC indicates that in plasma also conformational changes occur. In case of UV-irradiated PVC secondary, dark reactions (mainly oxidation) take place during storage at ambient conditions. (C) 2002 Elsevier Science B.V. All rights reserved.