An impact of the copper additive on photocatalytic and bactericidal properties of TiO₂ thin films

The biological and photocatalytic activity of TiO₂ and TiO₂:Cu in relation to their structure, surface topography, wettability and optical properties of the thin films was investigated. Thin-film coatings were prepared by magnetron sputtering method in oxygen plasma with use of metallic targets (Ti and Ti-Cu). The results of structural studies revealed that addition of Cu into titania matrix (during the deposition process) resulted in obtaining of an amorphous film, while in case of undoped TiO₂, presence of nanocrystalline anatase (with crystallites size of 20 nm) was found. Moreover, an addition of cooper had also an effect on surface diversification and decrease of its hydrophilicity. The roughness of TiO₂:Cu film was 25 % lower (0.6 nm) as-compared to titania (0.8 nm). These modifications of TiO₂:Cu had an impact on the decrease of its photocatalytic activity, probably as a result of the active surface area decrease. Antibacterial and antifungal properties of the thin films against bacteria (Enterococcus hirae, Staphylococcus aureus, Bacillus subtilis, Escherichia coli) and yeast (Candida albicans) were also examined. For the purpose of this work the method dedicated for the evaluation of antimicrobial properties of thin films was developed. It was revealed that Cu-additive has a positive impact on neutralization of microorganisms.