The invention provides a method for imparting antiviral properties to a hydrophilic polymeric material comprising preparing a hydrophilic polymeric slurry, dispersing an ionic copper powder mixture containing cuprous oxide and cupric oxide in said slurry and then extruding or molding said slurry to form a hydrophilic polymeric material, wherein water-insoluble particles that release both Cu.sup.++ and Cu.sup.+ are directly and completely encapsulated within said hydrophilic polymeric material.