Structure architecting of proton exchange membranes for fuel cell: Homo, alternate, and random diol-based copolymers vs. blending

Gathering different useful structural features simultaneously in a unique material is of high interest for product developers. In proton exchange membranes, the desired characteristics include proton conductivity, stability, flexibility, and strength. Different materials must be combined to attain all mentioned properties, otherwise lack of desired properties and performance might be occur. A designed strategy was presented in this paper to this end. A-S-AF alternate asymmetric monomer -comprised of bisphenol A and bisphenol AF- and sulfonated polymers thereof were synthesized first. Then, a comprehensive comparison with bisphenol A and AF homo diols-based sulfonated copolymers, bisphenol A and AF random hybrid diol-based sulfonated copolymers and blend membranes of bisphenol A- and AF-based sulfonated copolymers was conducted for 30 and 40 % degree of sulfonation. Suitable molecular weight, compatibility of constituents, mechanical integrity, and stability were attained. An applicable concept for other structures of membranes from this polymer category was represented. Proportional to the polymer composition, proton conductivity at 80 °C was in the range of 0.086–0.142 S/cm. Among all the samples, three copolymers of A-S-AF30, A-S-AF40, and A-AF40 revealed more stability in cell media with current density values of 784.85, 909.35, and 1111.70 mA/cm2 respectively, and A-S-AF30 membrane showed substantially the highest Fenton stability.