CVD Elaboration of Nanostructured TiO2‐Ag Thin Films with Efficient Antibacterial Properties

Nanostructured TiO2‐Ag composite coatings are deposited by direct liquid injection metal‐organic (DLI‐MO) CVD at 683 K in a one‐step process. Silver pivalate (AgPiv) and titanium tetra‐iso‐propoxide (TTIP) are used as Ag and Ti molecular precursors, respectively. Metallic silver nanoparticles are co‐deposited with anatase TiO2 on stainless steel, glass, and silicon wafers. The silver particles are uniformly embedded in the oxide matrix through the entire film thickness. The influence of the growth conditions, including injection parameters, is investigated on the chemical, physical, and structural characteristics of the coatings as well as on their anti‐bacterial activities. The bacterium Staphylococcus aureus is employed for anti‐bacterial tests. The films are bactericidal, according to the JIS Z 2801 standard test performed in the dark, when they contain less than 1 at.‐% of silver. Under UV irradiation they exhibit a photocatalytic activity which decays by increasing the silver content. As a result of this dual functionality, the TiO2‐Ag nanocomposite coatings show promising potentialities as long‐term anti‐bacterial surfaces since self‐cleaning can be achieved periodically under UV light in order to maintain an efficient anti‐bacterial activity in the dark or in visible light.