Poly(aryl ether sulfone)s containing sulfonated pentiptycene groups SPES-x-PPD are firstly synthesized through nucleophilic aromatic substitution polycondensation by using pentiptycene-6,13-diol, bis(4-hydroxyphenyl) sulfone and 4,4'-difluorodiphenyl sulfone, followed by postsulfonation with concentrated sulfuric acid at room temperature. The structures of SPES-x-PPD are characterized by IR, (1)H NMR and (13)C NMR spectra. These ionomers generally show high thermal stability. Transmission electron microscopic observations reveal that SPES-x-PPD membranes form well-defined microphase separated structures. SPES-40-PPD with the IEC value 2.36 mmol g(-1) shows conductivity of 2.6 x 10(-1) S cm(-1) which is much higher than that of perfluorinated Nation 117 membrane (1.1 x 10(-1) S cm(-1)) at 80 degrees C and 94% RH. At 80 degrees C and 34% RH, SPES-40-PPD membrane displays the conductivity of 2.7 x 10(-3) S cm(-1) which is comparable with that of Nafion 117 membrane (3.0 x 10(-3) S cm(-1)). (C) 2011 Elsevier B.V. All rights reserved.