Bactericidal and hydrophilic plasma deposited thin TiO2 films on glass substrate

In recent years, titanium dioxide has attracted a great deal of attention as a material for photocatalytic applications. These applications include antibacterial effect as well as photocatalytic air and water purification. Another property of TiO2 concerns a substantial increase of its surface hydrophilicity upon irradiation. The aim of this work is to investigate thin TiO2films obtained by RF PECVD technique with respect to hydrophilic and long-term bactericidal activity. Structural studies, carried out by Raman spectroscopy show that all the investigated coatings are amorphous. The films exhibit agglomerates, with their amount depending on energetic conditions of deposition. Adhesion measured by a scratch test shows that films deposited at higher RF power adhere better than those synthesized at lower power values. UV irradiation causes death of nearly 100% of Escherichia coli population on TiO2films. The irradiated films are still active for about 30 min after the end of UV exposure. A substantial decrease of water contact angle is also observed upon the irradiation of the films with UV light.