Advanced surface modification of ultra-high molecular weight poly(ethylene) by helium plasma immersion ion implantation

Plasma immersion ion implantation is an emerging, versatile, relatively simple and cost‐effective surface modification technique, alternative to conventional ion implantation. With this method even irregularly shaped objects can be uniformly treated, enhancing thus their surface properties. Ultra‐high molecular weight polyethylene is a principal biomaterial currently used in total joint arthroplasty, the wear of which and in particular the wear debris induced osteolysis is the main cause of the premature failure of the hip joint prostheses. In order to improve the wear resistance of ultra‐high molecular weight polyethylene, in this work it was surface treated by plasma immersion ion implantation in helium. Process parameters like acceleration voltage, fluence and fluence rate were varied systematically. X‐ray photoelectron spectroscopy was applied to monitor the surface chemical changes. Alterations induced in the surface mechanical and wear properties like hardness, reduced modulus and volume loss were determined by nanoindentation and multipass wear test measurements. The results demonstrate that the applied treatment can significantly modify the surface chemical and nanomechanical properties and increase the wear resistance of ultra‐high molecular weight polyethylene. Copyright © 2006 John Wiley & Sons, Ltd.