A method of forming an antimicrobial film, including providing a substrate with a polymer coating disposed thereon, the polymer coating including: an antimicrobial material, an inner surface contacting the substrate, and an outer surface opposite the inner surface; and extracting ions from the antimicrobial material toward the outer surface, such that the outer surface interacts with surface microorganisms. A composition, including a polymer; an antimicrobial material; and at least one of an organic solvent and an additive. The antimicrobial material comprises at least one of copper-containing glass particles, copper oxide particles, copper metal particles, copper salts, copper coordination complexes, cuprite crystals, and a combination thereof. Further, the additive can be selected to increase the oxidation resistance of the antimicrobial material.