The present investigation reports one-pot synthetic approach to develop cation exchange membranes (CEMs) via free radical polymerization which avoids the post functionalization step that involves use of hazardous chemicals. The CEM is composed of sodium styrene sulfonate (StSO(3)Na), methyl methacrylate, divinyl benzene, and polyvinyl chloride which is prepared by varying relative amount of vinyl monomers. The membranes shown improved ion-exchange capacity, water uptake, ionic conductivity, and stabilities (mechanical, chemical, and thermal). Among different CEMs, CEM-1 has shown significantly improved performance with 8.54 x 10(-2)S.cm(-1) proton conductivity and 2.71 meq. g(-1) proton exchange capacity.