A new PEM composite membrane comprising of polyvinyl alcohol (PVA), sulfonic acid functionalized CNT and fluorinated MMT has been fabricated. Composite polymer membrane has been prepared by simple solution casting method. Composite properties have been evaluated by using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and FTIR techniques. The proton conductivity, methanol crossover and water uptake properties of newly fabricated membrane have been studied. The polymer membrane shows good thermal properties. The water content is in the range of 35-45%. Especially, it has been found that the fluorinated MMT used in this study plays a decisive role in water uptake and acts as a hydrophobic surface for controlling the swelling. The proton conductivities and the methanol permeabilities of all the membranes are in the range of 10(-3) to 10(-2) S/cm and 2.08 x 10(-6) cm(2)/s at room temperature, respectively. (C) 2011 Elsevier B.V. All rights reserved.