ANTIBACTERIAL SiO2-Ag SOL-GEL LAYERS ON FLAT GLASSES

The sol-gel method was used to prepare SiO2 layers with Ag addition on float and Fourcault glass substrates. Homogenous layers were obtained, either colourless or with various intensities of yellow colouring, by modifying procedures described in the literature and by optimising conditions of layer preparation (time of sol ageing, temperature and time of heat treatment of layers). The quality and homogeneity of the layers were investigated by optical microscopy and the colour intensity was evaluated by spectrophotometry. Antibacterial properties of the layers were tested using Escherichia coli bacteria. An antibacterial effect was found for the layers prepared on the float glass substrate, but not for those prepared on the Fourcault glass substrate. Chemical changes caused by interaction of the layers with the glass substrate during heat treatment are discussed. Chemical durability of the layers in distilled water was investigated and it was found that the layers were attacked by distilled water (60 C) after relatively short time of exposure.