Asymmetric hydrogel-composite membranes with improved water permeability and self-healing property

Hydrogel-composite membranes fabricated using poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) hydrogel and a polyethersulfone (PES) support present a promising avenue toward developing self-healing membranes-membranes that autonomously heal from physical damage without any external intervention. The previously developed pore-filled structure, however, suffers from low water permeability, since the hydrogel spans the depth of the PES substrate. This study explores a new asymmetric architecture in which the hydrogel layer is asymmetrically confined to the top several tens of micrometers of a single side of the substrate. We present an approach to achieve this configuration based on controlling the viscosity of the acrylamido-2-methylpropanesulfonic acid (AMPS) monomer solution used during membrane fabrication. The asymmetric PAMPS composite membranes exhibited improved water permeability compared to their pore-filled counterparts, as well as nearly equal self-healing performance following the same mechanism of self-healing. The results of this study collectively suggest that asymmetric hydrogel composite membranes are a more promising route to developing practical water filtration membranes with self-healing capability.