A composition of matter comprising a water-swellable IPN or semi-IPN including a hydrophobic thermoset or thermoplastic polymer and an ionic polymer, articles made from such composition and methods of using such articles. The invention also includes a process for producing a water-swellable IPN or semi-IPN from a hydrophobic thermoset or thermoplastic polymer including the steps of placing an ionizable monomer solution in contact with a solid form of the hydrophobic thermoset or thermoplastic polymer； diffusing the ionizable monomer solution into the hydrophobic thermoset or thermoplastic polymer； and polymerizing the ionizable monomers to form a ionic polymer inside the hydrophobic thermoset or thermoplastic polymer, thereby forming the IPN or semi-IPN.
