“…The most utilized perfluorosulfonic acid (PFSA) membranes, such as Nafion, are composed of a very hydrophobic perfluoro backbone and polar side chains having sulfonic acid groups; the interconnected hydrophilic channels are, therefore, well developed, and can maintain high proton conductivity [4]. However, these PEMs have inherent drawbacks, which include high fuel permeability, low glass transition temperature, and poor thermomechanical properties above 80 °C [5,6]. These drawbacks have prompted the development of alternative PEMs using hydrocarbon-based polymers, including sulfonated poly(arylene ether sulfone)s (SPAES)s, because of their advantages, such as low gas permeability, high thermal stability, and structural diversity [7,8].…”