Blocks of phenolphthalein poly(ether sulforte) (PES-C) were implanted with 110 keV protons in four doses: 1 X 10(14), 5 X 10(14), 2.5 X 10(15), and 1.25 X 10(16) ions/cm(2). The structures of the pristine and implanted PESC blocks were characterized by FTIR-ATR and X-ray photoelectron spectroscopy (XPS), whereas their friction and wear behavior were investigated with an M-2000 friction and wear tester at room temperature in an ambient atmosphere. The results revealed that with an increased implantation dose, it took more time for the friction coefficient to become smaller and level off when the dose did not exceed 10(16) ions/cm(2). At the highest dose, 1.25 X 10(16) ions/cm(2), the friction coefficient started smaller but increased quickly and leveled off at a higher number. In addition, the wear rate first increased and then decreased. When the dose exceeded 10(16) ions/cm(2), the wear rate of the sample showed an obvious decrease. The FTIR-ATR spectra showed that partial degradation took place on the surface of PES-C after proton implantation, and when the dose reached or exceeded 2.5 X 10(15) ions/cm(2), a new broad peak between 1600 and 1800 cm I appeared, showing that a carbon-rich structure had formed on the sample surface. XPS analyses justified the FTIR-ATR results, including the formation of amorphous carbon and the partial degradation, which was responsible for the variety of friction and wear behaviors of PES-C. (c) 2006 Wiley Periodicals, Inc.