Polymeric Antimicrobial Coating Incorporating Spray‐Dried Hierarchical Copper and Silver‐Doped Copper Microparticles

Copper (Cu)‐ and silver (Ag)‐based composite coatings on fomite surfaces have been shown to be effective in reducing the spread of pathogens such as viruses and antibiotic‐resistant bacteria. Herein, a facile, scalable, one‐step spray‐drying protocol using ascorbic acid as a green reducing agent and water as the solvent was developed to prepare Cu and Ag‐doped Cu microparticles for subsequent composite antimicrobial coating preparation. Silver doping affected the overall particle size and the hierarchical structure within a particle, as evidenced by dynamic light scattering, small‐angle X‐ray scattering, and electron microscopy. Crystallinity was confirmed by X‐ray and electron diffraction, while the distribution of silver and copper within the spray‐synthesized microparticles was assessed through EDX elemental mapping and X‐ray photoelectron spectroscopy. Composite coatings were prepared by embedding the microparticles in polymethyl methacrylate (PMMA) matrix via in situ free radical polymerization using benzoyl peroxide and applied on glass and stainless‐steel substrates. The antimicrobial efficacy of these composite coatings was determined by observing complete inhibition of Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus bacterial strains. The practicality of the approach was further demonstrated by coating a fomite surface, a stainless‐steel door knob, with the microparticle‐embedded PMMA composite and observing complete inhibition of bacterial growth.