Versatile Surface Modification of Hydrogels by Surface-Initiated, Cu⁰-Mediated Controlled Radical Polymerization

Surface-initiated controlled radical polymerization mediated by a Cu⁰ plate (SI-Cu⁰ CRP) emerges as a versatile and efficient method for the functionalization of the exposed surfaces of hydrogels with a wide variety of polymer brushes. When a Cu⁰ plate is placed in contact with initiator-bearing hydrogel surfaces in the presence of ligand and monomer and under ambient conditions, it rapidly consumes dissolved oxygen from the reaction mixture, further acting as a source of catalyst and leading to the rapid growth of hydrogel-bound polymer chains. Three types of functional surfaces have been prepared as examples of the wide range of potential materials that can be synthesized in this way, including a hydrogel with a protective, hydrophobic surface, a lubricious hydrogel, as well as a hydrogel with thermally switchable frictional properties.