SPAEK-based binary blends and ternary composites as proton exchange membranes for DMFCs

Naphthalene-containing blend membranes, comprising sulfonated polyaryletherketone (SPAEK) as the primary matrix, and basic component polyazomethine (PAM), which has a chemical structure partially similar with SPAEK, were investigated as proton exchange membranes (PEMs). Further, a ternary-composite membrane was successfully prepared by introducing acid-functionalized polysilsesquioxane (POSS–SO3H) into SPAEK/PAM composite using a sol–gel process. The relevant properties of the PEMs, such as proton conductivity, methanol permeability, water uptake, and morphology were determined, and it was shown that the ternary-composite membrane, SPAEK/PAM/POSS–SO3H, showed a superior combination of properties for proton conductivity and methanol resistance. Its selectivity was 7.5 times higher than Nafion.