UV-induced graft copolymerization with mixed monomers such as styrene (St) and maleic anhydride (MAH) onto the surface of polyethylene-terephthalate (PET) films was carried out. The chemical properties and the morphology of the surface of grafted films were investigated via attenuated total reflection (ATR), scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. ATR images revealed that MAH was succeeded in being grafted. On the other hand, SEM and AFM analysis showed that many granules, which may be grafted St and MAH chains, formed after being treated for 40 s by UV light. The water contact angle of grafted film is about 43 degrees,which reduced sharply compared with pristine film. UV spectra of CTC, which was formed by St and MAH, provided the argument about the mechanism of formation of grafted chains. (c) 2006 Wiley Periodicals, Inc.