The problem remains unsolved in DMFCs applications that the increase in proton conductivity is usually caused the permeation of methanol. Herein, a novel kind of pore-filling membrane is investigated to meet this challenge. The porous substrate is fabricated from block poly (ether sulphone) with low degree of sulfonation, which form well-developed conductive channels owing to an aggregation of sulfonic acid groups, ensuring low methonal crossover and swelling ratio. The pore structures are achieved by a solution casting method which introduces alpha-cyclodextrin as the porogen. The resulting porous substrate possesses homogeneous opening pore structures. Then, the filling electrolyte, an organic-soluble tetrabutylammonium 4-vinylbenzene sulfonate, is used to fill the substrate and form a crosslinked network inside the pores to ensure high proton conductivity. The pore-filling membrane with block polymers shows higher proton conductivity (0.083 S cm(-1 )at 80 degrees C) than that prepared by random polymers (0.072 S cm(-1) at 80 degrees C). Compared with Naflon 117, the composite membrane exhibits higher dimensional stability (6.6%) and methanol resistance (4.0 x 10(-7) cm(2) s(-1)). Furthermore, the pore-filling membrane outperforms Naflon 117 with an open circuit voltage of 0.61 V as well as a maximum power density of 46.8 mW/cm(2) under 10 M methanol condition. (C) 2019 Elsevier Ltd. All rights reserved.