The Preparation Of TiO₂ Films By Peroxo-titania Acid Solution Method And Their Applications On Scalpel

Recently nano-titania films have been widely studied because of their advantageous properties,such as high photocatalytic, photovoltaic and photo-induced super hydrophilic. In order to prepare good TiO₂ films, many methods have been used, including magnetic sputter method, CVD e.t. Among them, Sol-gel method is one of the major methods preparing TiO₂ films. However, the traditional sol-gel methods can cause environmental problems because they use abundant organic solution or inorganic strong acid solution to avoid the hydrolyzation of Ti⁴⁺ iron, and this limits scale-up applications of sol-gel. This paper synthesized TiO₂ precursor solution by NH₃H₂O modified peroxo-titania acid (PTA) method. This new method took deionized water as solvent and H₂O₂ as complex and was environment-friendly and low cost. Futhermore, this paper fabricated TiO₂ films by dip coating, studied the influences of thermal treatment temperature and layers on the surface morphology, the crystal and the water drop contact angle, developed TiO₂-SiO₂ composite solution and TiO₂-SiO₂ films by combination of this new method and the SiO₂ sol-gel method, and finally compared them with TiO₂ solution and TiO₂ film respectively.PTA solution with NH3H2O was prepared by PTA method. Comparing with no-modified PTA solution, the viscosity of NH₃H₂O-Modified PTA solution decreased from 16.5 mPa·S to 5 mPa·S, and could be used to prepare TiO₂ films by dip coating. FTIR spectrum of dried TiO₂ precursor power showed that after 400℃thermal treatment, the–O-O- group and NH₃H₂O molecular were completely degraded, and the PTA acid molecular transformed to TiO₂ powers.The results of EDXA element analysis and XRD pattern showed that the stainless steel substrate was coated with TiO₂ film through dip coating method. AFM pictures appeared that thermal treatment and layer number had a great influence on the morphologic of the TiO₂ film surface, and the film obtained under 500℃thermal treatment and 3 layers conditions had the greatest roughness than films under the other conditions.TiO₂-SiO₂ composite solution was prepared by mixing PTA solution with SiO₂ colloid solution. The FTIR spectrum demonstrated that TiO₂-SiO₂ composite under 500℃thermal treatment conditions contained Ti-O-Ti,Ti-O-Si and Si-O-Si three different atomic combinations. The AFM photograph showed that TiO₂ phrase and SiO₂ phrase were distributed uniformly on the surface of stainless steels. The TiO₂-SiO₂ composite film surface had good hydrophilic properties.Simulative surgery and biological evaluations with TiO₂ coated scalpels were conducted. The eschars were obviously reduced on the TiO₂ films surface with three layers or four layers under 500℃thermal treatment and 80W power. TiO₂ film coat could prevent eschar of scalpel as well as Teflon coat did. The biological evaluation showed that the TiO₂ film had no cytotoxicity, no delayed hypersensitivity and no intracutaneous reactivity, so scalpels coated with TiO₂ film could be used securely on human surgeries.