Methods for making antimicrobial resins and for forming coatings comprising antimicrobial resins on substrate surfaces are disclosed. The methods involve providing a mixture comprising about 15 weight % to about 80 weight % of a hydrophilic acrylic oligomer, about 10 weight % to about 80 weight % of a multifunctional acrylic monomer, about 5 weight % to about 40 weight % of an adhesion-promoting acrylic or vinyl monomer, and about 0.1 weight % to about 15 weight % of a metal salt; and exposing the mixture to a radiation source to cure at least a portion of the mixture, thereby forming an antimicrobial resin.