Antimicrobial waterborne acrylic paint by the additive of graphene nanosheets/silver nanocomposite

In this work, the use of the nanocomposite of silver nanoparticles (NPs) and reduced graphene oxide (RGO), Ag-RGO, as a promising antibacterial agent to water-based acrylic paints has been investigated. The hybrid nanomaterial represented a strong antibacterial activity against two bacteria strains of Gram-negative of Escherichia coli (E. coli) and Gram-positive of methicillin-resistant Staphylococcus aureus (S. aureus). To prepare the antibacterial paint, 190 ppm Ag-RGO was added to the paint under sonication. By increasing the concentration of Ag-RGO in paint, the inhibition efficiency increased. The atomic force microscopy images showed that after 24 h incubation of E. coli and S. aureus bacteria with the antibacterial paint, their lengths decrease and degrade. The antibacterial activity of antibacterial paint against S. aureus was greater than that of E. coli. Also, the antibacterial activity of Ag NPs, RGO, and Ag-RGO was investigated. Among these nanomaterials, Ag-RGO has the highest antibacterial property so that its value of minimum inhibitory concentration for both E. coli and S. aureus is the same as 230 ppm. The minimum bactericidal concentration values for Ag-RGO was measured as 330 and 280 ppm for E. coli and S. aureus, respectively.