The possibility of developing low-cost commercial grafted and sulfonated Poly(vinylidene fluoride) (PVDF-g-PSSA) membranes as proton exchange membranes for fuel cell applications have been investigated. PVDF-g-PSSA membranes were systematically prepared and examined with the focus of understanding how the polymer microstructure (degree of grafting and sulfonation, ion-exchange capacity, etc) affects their methanol permeability, water uptake, and proton conductivity. Fourier transform infrared spectroscopy was used to characterize the changes of the membrane's microstructure after grafting and sulfonation. The results showed that the PVDF-g-PSSA membranes exhibited good thermal stability and lower methanol permeability.The proton conductivity of PVDF-g-PSSA membranes was also measured by the electrochemical impedance spectroscopy method. It was found that the proton conductivity of PVDF-g-PSSA membranes depends on the degree of sulfonation. All the sulfonated membranes show high proton conductivity at 92°C, in the range of 27 to 235 mScm, which is much higher than that of Nafion212 (102 mScm −1 at 80°C). The results indicated that the PVDF-g-PSSA membranesare particularly promising membranes to be used as polymer electrolyte membranes due to their excellent stability, low methanol permeability, and high proton conductivity. has high stability and good proton conductivity in low temperatures and high relative-humidity conditions. However, the Nafion-based PEM is expensive, and its conductivity showed reduction at higher temperatures (>80°C) and low humidity (<40%) conditions. A lot of studies have been performed with the goal of developing alternative membranes, focusing on the reduction of the methanol permeability. Some of them have worked on developing new synthetic polymeric membranes that have ionic clusters, [14][15][16][17] or the modification of the Nafion membranes by surface treatment or by blending them with other