Investigation on methanol permeability of Nafion modified by self-assembled clay-nanocomposite multilayers

Clay-nanocomposite thin films were deposited on the Nation membranes by layer-by-layer assembly, in order to enhance resistance of the membrane against methanol transport. The bilayers of exfoliated clay nanosheets and ionic polyacetylenes (PEPy-C18) were found to build up successfully on the substrate as the linear increase of UV-vis absorption intensity of the multilayer films. The TEM image of the cross-section of the multilayer films clearly showed that the clay nanosheet layers were lying parallel to the film surface and were regularly deposited to form ordered nanocomposite multilayer. Only 20 bilayer nanocomposites with a thickness of about 0.1 mum reduced the methanol permeability of the Nafion membrane to a half without deterioration of its in-plane proton conductivity. (C) 2004 Elsevier Ltd. All rights reserved.