We present a promising candidate for a hydrocarbon-based electrolyte membrane material, which shows higher fuel cell performance and durability than Nafion 212. Sulfonated poly(p-phenylene) (sPP)-based multi-block copolymers with optimized flexible hydrophobic blocks were synthesized using a Ni (0)-catalyzed cross-coupling polymerization. The resulting copolymers showed well-developed nanophase separation between the hydrophilic and hydrophobic domains and highly connected hydrophilic nanochannels, which gave rise to enhanced proton conduction and low dimensional variation. Moreover, the sPP-b-PAES(6.5K)-3.0 membranes with poly(arylene ether sulione) (PAES) oligomer as a hydrophobic block material exhibited a significantly higher fuel cell performance than Nafion 212 under fully and partially hydrated conditions. Furthermore, this material exhibited superior long-term stability compared with Nafion 212. To the best of our knowledge, this material is the first reported hydrocarbonbased ionomer that has both a fuel cell performance and durability that are superior to those of Nafion. (C) 2015 Elsevier B.V. All rights reserved.