Mahdi Tohidian - Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran
SeyyedEmadodin Shakeri
Seyyed Reza Ghaffarian
Mohammad Mahdi Hasani-Sadrabadi

The key part of DMFCs is proton exchange membrane (PEM).In this regard, the aromatic polymers such as sulfonated Poly(2,6-dimethyl-1,4-phenylene oxide) (sPPO),sulfonated poly(ether ether ketone) (sPEEK) and sulfonated poly (ether sulfone) (sPES) have been suggested and evaluated as alternative to Nafion and The optimum degree ofsulfonation was determined. To reduce the methanol cross over, organically modified montmorillonite (OMMT) was added by 1%wt to each optimum sulfonated matrix and The XRD patterns of nanocomposites proved the exfoliated structure of clay in all samples .The selectivity parameter – ratio of proton conductivity to methanol permeability– was identified and measured for each sample at 250c and the results were compared with nafion117. Finally The DMFC single cell assembled by the sPEEK based nanocomposites showed highest power density of 158mW.cm-2 in comparison with that of 135mW.cm-2, 118mW.cm-2 and 108mW.cm-2 for sPES, sPPO and Nafion® 117 membranes in a 5M methanol feed.