Polymers, and particularly conventional commodity bulk polymers, are modified to have a surface activity of interest using a surface modifying polymer that includes a moiety that favors migration to the surface of the bulk polymer together with a moiety provides the activity of interest (e.g., biocidal, wettability modifying (hydrophobic or hydrophilic), resistance to radiant energy, providing a functional group for functionalizing the surface, etc.). The surface modifying polymer is combined with the bulk polymer, and, due to the presence of the moiety that favors migration, concentrates primarily on the surface of the bulk polymer such that the moiety that provides the activity of interest is located primarily on the surface of the bulk polymeric article which is produced.