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Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition

Ponja, Sapna D., Sehmi, Sandeep K., Allan, Elaine, MacRobert, Alexander J., Parkin, Ivan P., Carmalt, Claire J.
ACS Applied Materials & Interfaces 2015 v.7 no.51 pp. 28616-28623
Escherichia coli, Staphylococcus aureus, X-ray diffraction, X-ray photoelectron spectroscopy, antibacterial properties, detection limit, glass, oxides, scanning electron microscopy, silver, silver nitrate, ultraviolet radiation, vapors
Silver thin films were deposited on SiO₂-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO₂-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activity of these samples was tested against Escherichia coli and Staphylococcus aureus in the dark and under UV light (365 nm). All Ag-deposited films reduced the numbers of E. coli by 99.9% within 6 h and the numbers of S. aureus by 99.9% within only 2 h. FTO/Ag reduced bacterial numbers of E. coli to below the detection limit after 60 min and caused a 99.9% reduction of S. aureus within only 15 min of UV irradiation. Activ/Ag reduced the numbers of S. aureus by 66.6% after 60 min and TiO₂/Ag killed 99.9% of S. aureus within 60 min of UV exposure. More remarkably, we observed a 99.9% reduction in the numbers of E. coli within 6 h and the numbers of S. aureus within 4 h in the dark using our novel TiO₂/Ag system.