Highly proton conductive and mechanically stable Nafion 112 based composite membranes with suppressed methanol permeability were prepared via Layer-by-Layer (LbL) technique for fuel cell applications. It was observed from UV-vis results that the polyelectrolyte layers growth on Nafion membrane surface regularly. (PAH/PSS)(20)-H(+) with 0.01 M NaCl exhibited 39.9% reduction in methanol permittivity and nearly 2 times higher proton conductivity (0.152 S cm(-1)) than that of untreated Nafion (R) 112. Promisingly, it was found that the membrane selectivity (Phi) values of all multilayered composite membranes in proton form prepared from polyelectrolytes comprising NaCl were higher than that of both untreated and chemically treated Nafion (R) 112. Furthermore, the mechanical and thermal properties of the composite membrane obtained from polyelectrolytes free salt were enhanced due to the interaction between the polar phase of Nafion and anionic/cationic charges of polyions. (C) 2010 Elsevier B.V. All rights reserved.