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

Control of the hydrophilic properties of hydroxyapatite Ca-10(PO4)(6)(OH)(2) (HAp) is important for the use of biocompatible materials. From this standing point, hydroxyapatite was implanted with N-2(+), O-2(+) and Ar+ with 1 X 10(17)-1 X 10(21) 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. Hydrophilic HAp surfaces were formed by N-2(+), O-2(+) and Ar+ implantations and plasma treatments of Ar, C2H5OH and CH3OH, with contact angles from 10 degrees to 60 degrees. Only the CF4 plasma treatment can form super-hydrophilic surfaces with contact angles of 4-8 degrees. The hydrophilic and super-hydrophilic formation mechanism was discussed based on analysis of XPS data. (c) 2004 Elsevier B.V. All rights reserved.