Easy scalable avenue of anti-bacterial nanocomposites coating containing Ag NPs prepared by cryomilling

Abstract

The antibacterial coating is required in many applications such as water treatment plants, healthcare surfaces, air conditioners, doors, etc, and the synthesis process is needed to be scalable for technologically viability. The addition of an antibacterial agent in the coating endows the antibacterial action of the coating with extended durability. Therefore, metal nanoparticles are the best alternatives to antibiotics and other hazardous substances. The production of nanoparticles in large quantity and their distribution in the coating is the biggest challenge. The cryomilling technique is known to capable of large-scale production of metal nanoparticles (NPs). Among the other metals, Ag metal nanoparticles exhibit the remarkable antibacterial property. In the present investigation the pristine free standing Ag NPs were prepared by the cryomilling (milling at <123 K temperature) and ex-situ added in the silica-based SOL synthesized by silicon alkoxide hydrolysis and condensation. The Ag NPs embedded silica sol has been deposited over glass coverslips and aluminum panels using a dip-coating technique. They were characterized in coating stability, nanoparticles homogeneous distribution, and antibacterial/anti-fouling property against Staphylococcus aureus and Escherichia coli bacterial strains. The sol-gel nanocomposite coating embedded with Ag NPs has been found to exhibit excellent antifouling property against both the bacterial cell lines with the highest antibacterial efficiency of 92 and 90 % against E.coli and S. aureus, respectively.