A simple and efficient procedure for the synthesis of ferrogels based on physically cross-linked PVA

Abstract

Ferrogels with well-dispersed single-domain magnetic nanoparticles (NPs) were obtained by the infusion of iron salts in physically cross-linked poly(vinyl alcohol) (PVA) hydrogels followed by coprecipitation. Freeze-thaw (F-T) cycling was used as a cryogenic technique to form mechanically strong and highly swellable hydrogels. The networked structure of the final material was used as a constrained environment for the precipitation of iron oxide NPs and formation of the magnetic gel. A homogeneous, single-domain ensemble of more than 15 wt % iron oxide NPs (in only one cycle of absorption) could be obtained through this easy technique. Moreover, the capacity of these magnetic ferrogels to absorb high amounts of ethanol/water solutions allows impregnation of these materials with ibuprofen and subsequent release of the drug at physiological pH. The biocompatibility of the components and the use of the nontoxic PVA cross-linking strategy (F-T cycling) make these materials promising for drug-delivery applications.