An acrylic acid (AA) grafted polyethylene (PE) film with a homogeneous distribution of grafted chains was prepared by the photografting of AA onto a low-density PE film with a thickness of 30 mu m. The AA-grafted PE film was Subjected to amidation with isopropylamine (IPA) at 25 degrees C in water as a solvent. Up to 80 mol % of the carboxyl groups of the AA-grafted chains Could be successfully converted to N-isopropylacrylamide (NIPAAm) residues through the control of the amidation conditions, such as the reaction time, amount of the condensation reagent, and concentration of IPA. The resulting amidated PE film exhibited a temperature-responsive character: the film swelled and shrank in water below and above a temperature range of about 40-60 degrees C, respectively. The extent of the character of the amidated PE film was greater than that of NIPAAm- and NIPAAm/AA-grafted PE films prepared by the photografting of NIPAAm monomer and NIPAAm/AA binary monomers, respectively. (C) 2009 Wiley Periodicals, Inc. I Appl Polym Sci 112: 685-691, 2009