Primer formulations with antibacterial properties for murals

Primers for Thai mural paintings were traditionally made of natural components, particularly tamarind glue and clay. However, this traditional mixture is sensitive to environmental factors, including climate conditions and microorganisms, because these components encourage microbial growth. This research aimed to add an antibacterial property to the traditional primer and to formulate functional primers with antibacterial behaviour, scrub resistance and washability. Titanium dioxide (TiO2) and silver nanoparticles (AgNPs), which have antibacterial properties, were used in the formulations. The antibacterial properties were tested against four bacterial species: Bacillus subtilis, B. cereus, B. mycoides, and Leclercia adecarboxylata, which had been found on the mural painting surface of the Somanas Rajavaravihara temple in Bangkok, Thailand. The presence of TiO2 and AgNPs in the modern functional primers inhibited the growth of these four bacterial species, while neither the traditional primer with AgNPs nor the one without showed inhibitory activity against all four bacterial species. We also tested the scrub resistance and washability of the modern functional primers compared to the traditional primer.