METHACRYLATE-CAPPED FLUORO SIDE-CHAIN SILOXANES - SYNTHESIS, CHARACTERIZATION, AND THEIR USE IN THE DESIGN OF OXYGEN-PERMEABLE HYDROGELS

Methacrylate end-capped 3-(2,2,3,3,-tetrafluoropropoxy)propyl, 3-(2,2, 3,3,4,4,5,5-octafluoropentoxy)propyl, and ,3,3,4,4,5,5,6,6,7,7-dodecaf luorotridecoxy)-propyl side chain siloxanes were evaluated for potenti al use in hydrogels for contact lens application. The preparation of t he methacrylate end-capped perfluoro side chain siloxanes was accompli shed in two relatively simple synthetic steps. The first step consiste d of the acid-catalyzed co-ring opening polymerization of octamethylcy clotetrasiloxane, tetramethylcyclotetrasiloxane, and 1,3-bis-methacryl oxybutyltetramethyldisiloxane, followed by a platinum-catalyzed hydros ilation with the tetrafluoro-, octafluoro-, and dodecafluoro-substitut ed allylic ethers. The incorporation of the terminal [-CF2-H] function ality had a dramatic effect on the increased solubility of the fluoro siloxane with hydrophilic monomers. Radical bulk polymerization of the methacrylate-capped fluoro side chain siloxanes with hydrophilic mono mers, such as dimethylacrylamide and N-vinyl pyrrolidinone, resulted i n transparent hydrogels possessing a wide range of water contents, hig h oxygen permeability, and a low modulus of elasticity. (C) 1997 John Wiley & Sons, Inc.