Bio-Activation of Polyether Ether Ketone Using Plasma Immersion Ion Implantation: A Kinetic Model

Plasma immersion ion implantation (PIII) is used in this study to improve the surface bioactivity of polyether ether ketone (PEEK) by modifying the chemical structure and introducing radicals. The kinetic properties of the treated surface are characterised here, allowing for tuning of the PIII process in order to produce PEEK with optimised bioactivity. The optimum PIII ion fluence for PEEK is determined to be 1x10(16) ions/cm(2). A model is proposed that accounts for the decay of radicals, nitrogen loss, oxygen incorporation and changes in surface energy within the structure. The model is based on the premise that there is a distribution of local chemical environments produced by PIII. The distribution of chemical environments results in a bioactive surface that has a long shelf life, compatible with clinical needs.