Heterogeneous cation exchange membranes were prepared by solution casting technique using S-polyvinylchloride (S-PVC) and Styrene-Butadiene-Rubber (SBR) as binder and cation exchange resin as functional groups. In this research the effect of sodium dodecyl sulphate (SDS) on the selectivity, structure and electrochemical properties of potential driven membranes using this material in casting solution was evaluated. Totally the experiments revealed that SDS by revaluation in structure of membrane could change the membrane performance. The microstructures of prepared membranes were investigated by scanning optical microscopy (SOM). The images show that the enhancement in SDS ratio in the casting solution results in uniform distribution of functional groups. In order to investigate these prepared membranes, the oxidative stability and electrochemical properties tests were used. The measurements indicate that oxidative stability, ion exchange capacity, ion permeability, surface resistance, membrane potential, ionic flux, current efficiency, and selectivity parameters of prepared membranes have been improved by up to 2 wt% increase in SDS in the casting solution. Membrane with 2 wt% SDS loading exhibited higher efficiency and electrochemical properties in comparison with other prepared membranes in this research, while its water content was lower than other membranes. (C) 2010 Elsevier B.V. All rights reserved.