Surface-modified polypropylene (PP) films with thermally and photochemically sensitive copolymers consisting of N-(2-hydroxypropyl)methacrylamide (HPMA) and 4-(4-methoxvphenylazo)phenyl methacrylate (MPAP), poly(HPMA-co-MPAP)-g-PP (abbreviated g-PP) film, were prepared by graft copolymerization with an Ar-plasma postpolymerization technique. The surfaces of the g-PP films were characterized by means of X-ray photoelectron spectroscopy; the percentage grafting of poly(HPMA-co-MPAP) with a number-average molecular weight of 3.28 x 10(4) was 7.12%, and the molar ratio of HPMA-MPAH in the copolymer was 0.75:0.25. The stimuli-sensitive adsorption of albumin and polystyrene microspheres on the g-PP film was also measured. (C) 2003 Wiley Periodicals, Inc.