Comparison of Structure and Properties of TiO_2 Films Synthesized by Sol-Gel and Ion beam on Biomedical NiTi Alloy

In order to improve the biocompatibility of NiTi alloy, TiO2 films were synthesized on the surface by sol-gel and Ion beam enhanced deposition (IBED) methods, respectively. The structure, surface morphology and composition of the films were studied comparatively by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS). The electrochemical corrosion measurement shows that the two kinds of TiO2 films both can improve the corrosion resistance of metallic biomaterials in simulated body fluid as a protective layer on the surface. In order to further improve the anticoagulation of implants, immobilization of heparin molecule on the film surface was also investigated. The results indicate that sol-gel-derived TiO2 film can obtain better heparin immobilization effects than Ion beam derived TiO2 film.