Synthesis and properties of oxygen permeable hydrogels based on copolymers of dimethylacrylamide and fluoro sulfonamide (meth)acrylates

Xerogels have been synthesized from copolymers of dimethylacrylamide and 2-(N-alkylperfluoro-octanesulfonamido)ethyl (meth)acrylates. The xerogels exhibit transparency despite the fact that DSC analyses reveal heterogeneous structures exhibiting two glass transition temperatures. The DSC results are indicative of a morphology made up of domains corresponding to a rigid backbone and flexible perfluorinated side-chains. On swelling in saline hydrogels were formed. The resulting materials maintain transparency, display high water contents (40-80 wt%) and moduli comparable with existing commercial hydrogel materials. The oxygen permeabilities (Dk x 10¹⁰) of the gels range from 34 to 52 (ml O₂) mm cm^-2 s^-1 mmHg^-1. These Dk values are high in comparison with those of conventional hydrogels and are indicative of a heterogeneous hydrogel structure facilitating oxygen transmission through both the aqueous phase and via a fluorine-rich co- continuous polymeric phase.