Organically modified ZnO nanoparticles incorporated emulsion paints for antibacterial activity

The increasing issue of surface contamination highlights the urgent need for antibacterial nanocomposite coatings as durable and effective solutions for infection control in various fields. This study focuses on developing antibacterial nanocomposite emulsion paints by synthesizing zinc oxide nanoparticles (ZnO NPs) and incorporating them into water-based emulsion paints. ZnO NPs were synthesized via a precipitation method using zinc acetate dihydrate and oxalic acid dihydrate, followed by surface modification through a sol-gel reaction with vinyltriethoxysilane (VTES). The modified ZnO NPs (V-ZnO) were characterized using FTIR, XRD, DLS, SEM, and EDS techniques. These nanoparticles were then incorporated into a butyl acrylate-methyl methacrylate (BA-MMA) copolymer at varying concentrations (0–3 wt. % of the total monomer) through conventional emulsion polymerization, and their mechanical, chemical, and thermal properties were assessed. A commercial emulsion was also analyzed for comparison. White emulsion paints were subsequently formulated using the emulsions containing V-ZnO nanoparticles as binders, alongside titanium dioxide (TiO₂) as a white pigment, talc and calcium carbonate as extenders, and various additives to enhance coating properties. The paints formulated were applied on masonry substrates and tested for mechanical, chemical, and antibacterial properties. Antibacterial activity was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria using agar disk diffusion and broth dilution methods. The results indicated that emulsion paints containing 1 % V-ZnO nanoparticles exhibited the highest antibacterial activity against both Gram-positive and Gram-negative bacteria. These nanocomposite emulsion paints show significant potential for use in healthcare facilities, schools, and other public spaces where controlling the spread of infectious diseases is essential.