Effects of silver concentrations on microstructure and properties of nanostructured titania films

• Nanostructured TiO2 films with different concentrations of silver were prepared.
• The effects of silver concentrations on microstructure and properties were studied.
• The films exhibit excellent antibacterial property and corrosion resistance.
• The hardness of the antibacterial TiO2 films is also improved.

To prevent bacterial proliferation on biomedical titanium implants, significant efforts have been focused on modifying its surface composition and structure. In this study, nanostructured titania (TiO2) films with different concentrations of silver were prepared by magnetron sputtering and subsequently annealed at 600 °C in air. The effects of silver concentrations on microstructure, antibacterial property, corrosion resistance and hardness were studied. The results indicate that silver contribute to the growth of the TiO2 grains and is uniformly dispersed on the surface of annealed samples. The annealed films with a thickness of about 2.5 μm are uniform and mainly composed of rutile phase and pure titanium. Silver mainly exists in the metallic state in the TiO2 films. The Ag-doped TiO2 films can effectively kill Staphylococcus aureus within 24 h and the antibacterial ability increases with the silver content. The dynamic potential polarization results show that silver incorporation into TiO2 films slightly lower the corrosion potential, but significantly decrease the current density, and the current density decreases as the silver addition increases. Moreover, the hardness of the Ag-doped TiO2 films is also greatly improved.