Preparation and antibacterial effects of Ag–SiO2 thin films by sol–gel method

In the present study, silver-doped silica thin films were successfully prepared by sol–gel method to apply for antibacterial materials. The starting solution was prepared from 1:0.24:3.75:2.2 molar ratios of Si(OC2H5)4):AgNO3:H2O:C2H5OCH2CH2OH and then the pH value controlled at 3 with 0.5 HNO3 solution. The formation of silver-doped glassy silica thin films at various temperatures was investigated through infrared spectroscopy, ultraviolet–visible, scanning electron microscopy and X-ray diffraction. From these analysis data, it was found that silver ions were completely trapped in the silica matrix and their reduction could be achieved at 600°C annealing temperature. The antibacterial effects of silica thin films against Escherichia coli and Staphylococcus aureus were examined by film attachment method. The coating films had an excellent antibacterial performance.