Synthesis and characterization of covalently interconnected phosphazene - Silicate hybrid network membranes

A method for the cross-linking of water-soluble polyphosphazenes via a sol-gel condensation is described. Precursor polymers were produced by covalently binding an organosilicon alkoxide to the terminus of pendent oligoethylenoxy chains on poly[bis(methoxyethoxyethoxy)phosphazene]. Subsequent hydrolysis and condensation of these precursors yielded hybrid silicate networks with covalently integrated polyphosphazenes. The hybrid networks showed high water uptake values (up to 1570 wt %). The release of Rose Bengal, Biebrich Scarlet, and FITC-albumin from the phosphazene-silicate matrix was studied over time as a function of network density. These hydrogels are of interest as potential materials for use in membranes or biomaterials.