Porous polysulfone membrane, prepared by a phase-inversion technique, is filled with (3-acrylamidopropyl)trimethylammonium chloride and N,N'-methylenebisacrylamide via interfacial diffusion. The impregnated membrane is then subjected to UV-irradiation for polymerizing monomers that are entrapped in pore channels of the membrane. This in-situ polymerization engenders a grid-plug microstructure, where the grid is polysulfone and the plugs are an ion (OH(-)) conducting phase. As the plugs are extensively interconnected and non-tortuous throughout the membrane matrix, the ion-conducting phase sustains a power density as high as 55 mW cm(-2) at 60 degrees C. Thermal analysis indicates that the pore-filling condition affects the packing density of the plugs that in turn, impacts on ion transport flux. (C) 2011 Elsevier B.V. All rights reserved.