Stability of silicones modified with PEO-silane amphiphiles: Impact of structure and concentration

Abstract

The efficacy of poly (ethylene oxide) (PEO)-based surface-modifying additives (SMAs), following the bulk-modification of silicones, requires sustained, water-driven PEO migration to the surface to achieve hydrophilicity and subsequent reduction of protein adsorption. Herein, a condensation cure silicone was modified with PEO-silane amphiphile SMAs (5–100 μmol per 1 g silicone) comprised of an oligo (dimethyl siloxane) (ODMS) tether, PEO segment and optional triethoxysilane (TEOS) crosslinkable group. This allowed us to confirm that the TEOS crosslinkable group was not necessary and that the ODMS tether (m = 13 or 30) could sufficiently physically anchor the amphiphile in the silicone network. Surface hydrophilicity was examined before and after aqueous conditioning, as well as mass loss and water uptake after conditioning. Overall, silicones modified with all amphiphilic SMAs produced increasingly hydrophilic surfaces and their hydrophilicity was maintained following conditioning. At all concentrations, all amphiphilic SMA modified silicones had minimal water uptake and mass loss, comparable to that of unmodified silicone. Finally, silicones modified with all amphiphilic SMAs ≥25 μmol exhibited exceptional protein resistance that was not appreciably diminished after conditioning.