Preparation And Property Of TiO₂-PTFE Composite Film

Over the past decade, much attention has been paid to biomedical compatibility of materials applied in artificial organs. Surface modification has shown potential to improve the compatibility of biomedical devices and materials. In this paper, titanium, a biologically nontoxic metal, has been chosen and applied in vascular stents as our modifiable material. The TiO₂ has been gained by the method of anodic oxidation.The TiO₂ films were fabricated using anodic oxidation method. By adding the polytetrafluoroethylene (PTFE) emulsion into the sulphuric acid electrolyte, the TiO₂-PTFE composite films were prepared through the method of anodic oxidation. The structure, component, and micromorphology of the films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Atomic force microscope (AFM), and Scan electronic microscope (SEM). Contact-angle measurement was used to investigate the characteristics of TiO₂ films and composited TiO₂-PTFE film surface.The SEM results showed that, many small holes could be seen on the titanium surface. The holes size are about from 200 nm to 300nm in diameter, While adding PTFE into electrolyte liquid, films holes may be fully filled with PTFE particles whose diameter was about 150nm. The XPS analysis indicated that the F element is existed in films. The change of contact angle shows the difference of the composition films in chemical composition and morphology. The parameters of anodic oxidation such current, voltage, the concentration of electrolyte and the concentration of PTFE have been chosen by the characteristics of the films.The results of blood platelet adhesion experiment indicated that, compared to stainless steel or TiO₂ surface, the TiO₂ film and the TiO₂-PTFE composition films possessed better blood platelet adhesion behavior (fewer and no deformation). According to HUVEC adhesion test results, the composition film has the same or better biomedical response than traditional TiO₂ biomaterials and Ti spontaneously formed oxide surface. Hence, TiO₂-PTFE composition materials are a potential substitute to traditional TiO₂ biomaterials.All these results indicated that the TiO₂ and TiO₂-PTFE, produced by anodic oxidation, has the same or even better biomedical response than traditional Ti biomaterials, and much better blood compatibility. This method maybe lead a new way to composition metal with biodegradable poly (lactic acid) nanoparticles.