The surface of a polypropylene (PP) film was activated with chemical, electrochemical, and physical methods, and the effectiveness of these methods was compared. The effects of PP activation were assessed with attenuated total reflection IR spectroscopy (ATR-IR), SEM microscopy, and an analysis, based on the liquid contact angle, of the free energy components of the surface. The activation of the PP surface, which was dependent on the oxidizing medium, increased the energy of the PP surface layer and formed new chemical (carbonyl) groups, which were identified by IR (ATR) absorption spectroscopy and confirmed by selective surface dyeing. The treatments were ranked in the following order of increasing effectiveness: UV irradiation < 3M nitric acid < 30% hydrogen peroxide < silver nitrate (electrochemical method) < chromic mixture. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2071-2080, 2011