In order to meet the requirement of proton exchange membranes in direct methanol fuel cells (DMFCs)

sulfonated poly(aryle ether ketone sulfone)/polypyrrole (SPAEKS/PPy) composite membranes with different contents of PPy were prepared in chemical in situ polymerization by means of ion-dipole interaction between the sulfonate groups of SPAEKS and imino groups of polypyrrole.The incorporation of polypyrrole particles into the clusters

which was the transport pathway

could change the morphology of the SPAEKS matrix.FTIR spectra suggested that the sulfonic acid groups on the copolymer backbone strongly interacted with amonium groups of PPy.SEM pictures showed that the PPy particles were uniformly distributed not only in regions near the surface but also in the internal space of the SPAEKS membranes matrix.The composite membranes showed good thermal stability

low water uptake

low swelling ratio both at length and thickness and relatively high proton conductive capability.The methanol diffusion coefficient (1.18×10-7 cm2/s) of SPAEKS/PPy-3 composite membranes is much lower than that of pure SPAEKS membranes (8.52×10-7cm2/s).At the same time

the selectivity increased with increasing the molar ratio between PPy and the sulfonate groups

meaning that the composite membranes have more impact on the reduction of methanol diffusion coefficient than that on proton conductivity.The selectivity of SPAEKS/PPy-3 composite membranes is much higher than that of pure SPAEKS membranes and other composite membranes

which suggests that the composite membranes with 0.99 molar ratio between PPy and the sulfonate groups of SPAEKS are promising as proton exchange membranes for DMFC applications.