Surface modification on polytetrafluoroethylene (PTFE) films was performed with sequential hydrogen plasma/ozone treatments and surface-initiated polymerization. C-H group.,; were introduced to the surface of PTFE films through defluorination and hydrogenation reactions under hydrogen plasma treatment. The C-H groups then served as ozone accessible sites to form peroxide groups under ozone treatment. Grafting polymerization initiating from the peroxide groups was performed on the PTFE film surface with using acrylamide, acrylic acid, glycidyl methacrylate and 2-(2-biomoisobutyryloxy)ethyl acrylate (BIEA) as monomers. With utilizing the isobutylbromicle groups on the surface of: PTFE-g-PBIEA film as initiators, sodium 4-styrenesulfonate (NaSS) was polymerized onto the PTFE film surface via atom transfer radical polymerization. to bring arborescent macromolecular structure to PTFE film surface. The chemical structures of the macromolecules on PTFE film surfaces were characterized with FTIR-ATR, SEM-EDX and XPS. The surface hydrophilicities of modified PTFE films were significantly enhanced with the modification. (c) 2005 Elsevier Ltd. All rights reserved.