Preparation of Ag/TiO2/PA Self-Cleaning Paint by In-suit Polymerization and Its Antimicrobial Properties

Using the materials of butyl-titanate, acetic acid, ethanol, the concentrated solution containing about 250 nm nano-TiO2 particles was prepared, the size distribution coefficient of 0.631. Polycrystalline nano-TiO2 particles were examined by transmission electron microscopy (TEM) and the laser particle size analyzer. Adopting this stable concentrated solution, we obtained the nano TiO2 modified poly acrylic acid resin (TiO2/PA) coating on aluminum foils. From UV-vis spectra and diffuse reflectance spectroscopy spectra (DRS), it is found that the nano-TiO2 particles have a strong absorption effect on the UV. Using the concentrated solution-modified additive and the method of in-situ polymerization, the coating could generate Ag nanoparticles, and finally Ag/TiO2/PA coating was obtained. According to the national standard GBT 1741-2007 Anti-mold test, the Ag/TiO2/PA exterior wall coating had no significant mold growth. For TiO2/PA coating, we are invisible or difficult to see the long bacteria, but the long bacteria can be seen clearly under a magnifying glass phenomenon. Ag/TiO2/PA has a strong antibacterial activity on Escherichia coli and Staphylococcus aureus, and its minimum inhibitory concentration (MIC) is of 7.285x10(-5) mg/mL. The antibacterial effect of Ag is obvious, but it could not eliminate toxic substances released by the dead bacteria. Relying on the photocatalytic properties of three films, its efficiency was tested with methyl orange (MO) under visible light by UV-vis spectrophotometer at 464 nm. After 2.5 h the decolorization rate is close to 50%, and the reason of photocatalytic ability of the coating is subject to mass of TiO2 on the surface.