Montmorillonite (MMT) was modified by two types of cationic fluorosurfactants in order to improve compatibility with and dispersion within Nafion((R)) membranes. Perfluoropolyether-containing cationic surfactant improved efficiency, by improving the barrier properties of Nafion((R)) towards methanol. Moreover, the fluoro-modified MMT had no deleterious impact on the ionic conductivity of the membranes in contrast to conventional organo-modified MMT. The performances of a small size fuel cell were accordingly improved. (c) 2006 Elsevier B.V. All rights reserved.