Hygroscopic-oxides/Nafion((R)) hybrid membranes were prepared using an infiltration sol-gel process, and the effects of infiltrated oxides on transport and direct methanol fuel cell (DMFC) properties were investigated at 25 degrees C. The inorganic contents were controlled by the infiltration time. Methanol permeability decreased with increasing infiltrated oxides. Spin-lattice relaxation measurements using H-1 nuclear magnetic resonance (H-1 NMR) spectroscopy suggested that the ionic channels of Nafion((R)) become narrow after infiltrating oxides. The hybrid membrane infiltrated with around 3 wt% oxides showed better DMFC performance than Nafion((R)). Impedance analysis suggested that the infiltrated oxides effectively reduce the charge transfer resistance. (c) 2006 Elsevier B.V. All rights reserved.