Formation of super-hydrophilic surface of hydroxyapatite by ion implantation and plasma treatment

Control of the hydrophilic properties of hydroxyapatite Ca10(PO4)6(OH)2 (HAp) is important for the use of biocompatible materials. From this standing point, hydroxyapatite was implanted with N2+, O2+ and Ar+ with 1×1017–1×1021 ions m−2 at an energy of 20 keV. It was also immersed in an RF plasma of Ar, C2H5OH, CH3OH and CF4 induced at RF power of 50–150 W. Contact angles for various specimens were measured and the formation mechanism of hydrophilic surfaces are discussed. hilic HAp surfaces were formed by N2+, O2+ and Ar+ implantations and plasma treatments of Ar, C2H5OH and CH3OH, with contact angles from 10° to 60°. Only the CF4 plasma treatment can form super-hydrophilic surfaces with contact angles of 4–8°. The hydrophilic and super-hydrophilic formation mechanism was discussed based on analysis of XPS data.