Phenolphthalein poly(ether sulfone) (PES-C) was implanted with 110 keV protons in four doses of 1 X 10(14), 5 X 10(14), 2.5 X 10(15), and 1.25 X 10(16) ions cm(-2). The friction and wear properties of both implanted and unimplanted PES-C were investigated with a THT07-135 high-temperature tribometer against a steel ball. Results revealed that the friction coefficient and wear rate both decreased with increasing doses: especially when the dose reached 1.25 X 1016 ions cm(-2), its wear rate decreased nearly two orders of magnitude. Scanning electron microscopy results revealed that the size of wear debris of unimplanted PES-C was greater than that of the implanted one. The worn surface of unimplanted PES-C showed plastic deformation, plastic flow, and adhesiveness, whereas the worn surface of the implanted one showed only some mild nicks. The carbon element distribution map revealed that much more carbon element transferred to the counterpart steel ball friction against the implanted PES-C. The IR spectrum showed that partial degradation might occur when PES-C was implanted with protons. Measurement of hardness revealed an increase with increasing doses. The reason for the increase might be the formation of carbon-rich structures on the surface of the sample. From the above, conclusions can be drawn that the wear mechanisms of unimplanted samples were mainly related to adhesion, plastic deformation, and plastic flow, whereas that of implanted samples was mainly attributed to mild "three-body" wear. (C) 2004 Wiley Periodicals, Inc.