A novel sulfonated monomer sodium-3-(4-(2,6-difluorobenzoyl)phenoxy)propane-l-sulfonate was designed and synthesized. Based on above monomer, a series of sulfonated poly(arylene ether) copolymers containing aliphatic acid groups between aromatic backbones and sulfonic acid groups (PSOA-SPAE) were successfully prepared by direct copolymerization. Ion exchange capacity (IEC) of the copolymers could be mediated in the range of 1.07-1.61 meq g(-1) by the monomer ratios used in the copolymerization. These copolymers exhibited good oxidative and dimensional stability. The proton conductivities of copolymer films increased with the increase of IEC and temperature. The conductivity of PSOA-SPAE-80 was 4.94 x 10(-2) S cm(-1) at room temperature, and was up to 1.35 x 10(-1) S cm(-1) at 100 degrees C, which was close to that of Nafion 117. These copolymers may be promising proton exchange membranes (PEMs) due to their high proton conductivity and good oxidative and dimensional stability. (C) 2008 Elsevier B.V. All rights reserved.