The free-radical polymerization of styrene initiated from a functionalized poly(ethylene terephthalate) (PET) surface yielded a tethered polymer layer. The anchoring of the initiator species on the PET surface was performed from surface-reactive groups easily generated by an alkaline hydrolysis of PET. After each surface modification, PET films were characterized by X-ray photoelectron spectroscopy, measurements of water contact angles, and time-of-flight secondary-ion mass spectrometry. The influence of the polymerization duration, the grafted initiator density, and the grafting mode on the efficiency of the surface-initiated polymerization of styrene was investigated. In some cases, the tethering of the polystyrene layer on PET could be a reversible process. (C) 2003 Wiley Periodicals, Inc.