Ion beam induced modifications of biocompatible polymer

Ion beam bombardment has shown great potential for improving the surface properties of polymers. In this paper, the ion beam-polymer interaction mechanisms are briefly discussed. The main objective of this research was to study the effects of H-ion beam on physico-chemical properties of Ultra-high-molecular-weight polyethylene (UHMWPE) as it is frequently used in biomedical applications. UHMWPE was bombarded with 65 keV H-ions to fluences ranging from 1x1014–2x1016 ions/cm2. Changes of surface layer composition produced by ion bombardment of UHMWPE samples were studied. The hydrogen release and oxygen uptake induced by ion beam bombardment were determined by Nuclear reaction analysis (NRA) using the1H(15N, αγ)12C and Rutherford backscattering spectrometry (RBS), respectively. Tribological and hardness properties at the polymer near surface region were studied by means of friction coefficient and micro-hardness testers, respectively. Wettability of the bombarded surfaces was determined by measuring the contact angle for distilled water. The obtained results showed that the ion bombardment induced hydrogen release increases with the increasing ion fluence. An important effect observed, was the rapid oxidation of samples, which occurs after exposure of bombarded samples to air. These effects resulted in important modifications of the surface properties of bombarded material such as change of friction coefficient, hardness and improved wettability. © (2015) Trans Tech Publications, Switzerland.