pH-sensitive membranes with crosslinked poly(acrylic acid) hydrogel for controlled delivery

Abstract

Polymeric pH-sensitive membranes and hydrogels are interesting materials for the controlled delivery of chemical agents triggered by external stimuli. In this contribution, we present a novel membrane design consisting of a polyethersulfone polymeric base and a crosslinked poly(acrylic acid) hydrogel containing pH-responsive carboxyl groups. Membranes were prepared using the modified traditional liquid phase inversion process. Solutions containing all membrane precursors were cast on a glass plate and cured by UV irradiation. UV curing was followed by immersion into the water bath to achieve phase separation and solidification. Obtained membranes exhibited high ion-exchange capacity and a moderate swelling degree dependent on the crosslinker properties. Studies of membrane loading with methylene blue and subsequent release of methylene blue from the membrane into the alkaline and acidic buffered solutions demonstrated pH-dependent delivery kinetics.