polymer - based biomaterials are popular due to ease of fabrication and low costs . however , many polymer substrates have undesirable surface properties . the invention provides a procedure to covalently apply a graft polymer to the surface of a polymer substrate by ultraviolet graft polymerization . the graft polymer is formed from monomers such as peg , aa , monomethoxy acrylate peg , hema , or dma . also , mixed monomers may be used to create the graft and the surface properties of the graft may be tailored for different properties , including hydrophobicity , friction coefficient , electroosmotic mobilities and electrophoretic separations . the invention has particular utility in tailoring surface chemistries in ocular lenses and polymer microdevices . i . ii . r : — oh acrylic acid — nh 2 acrylamide — n 2 dimethylacrylamide — och 2 ch 2 oh 2 - hydroxyethylacrylate — o n ch 3 peg monomethyoxylacrylate