High‐Performance Sultone‐Modified <scp>PVA</scp> / <scp>PAMPS</scp> Semi‐ <scp>IPN</scp> Hydrogels for Proton Exchange Membranes

ABSTRACT Hydrogel membranes composed of poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPS) and sultone‐modified poly(vinyl alcohol) (PVA) were successfully synthesized and evaluated as promising proton‐conducting materials. A key advantage involves the premodification of PVA with 1,3‐propane sultone to introduce sulfonic acid groups, thereby imparting proton conductivity to the PVA backbone. This sultone‐modified PVA was then physically entangled within a PAMPS cross‐linked network to form novel semi‐interpenetrating network (semi‐IPN) hydrogels. This synergistic design leverages the excellent film‐forming and mechanical properties of PVA with the high proton conductivity inherent to PAMPS. The synthesized membranes exhibited robust mechanical properties, with tensile strengths ranging from 5 to 30 MPa and percentage elongations between 200% and 400%, depending on their humidity content. These hydrogel membranes demonstrated proton conductivities ranging from 0.6 to 4.3 × 10 −2 S cm −1 . The activation energy for proton conduction was found to be as low as 3.5 kJ mol −1 , significantly lower than that of the commercial benchmark membrane, Nafion 117 (12 kJ mol −1 ). These findings underscore the potential of these novel PAMPS/sultone‐modified PVA semi‐IPN hydrogel membranes for advanced fuel cell applications.