A homogeneous Krytox-Si-Nafion((R)) hybrid membrane is proposed. The hybrid material is successfully prepared using Krytox 157 FSL whose structure is similar to that of Nafion((R)). Krytox 157 FSL is coupled onto a silica surface via a silane coupling agent to obtain the Krytox-Si. Krytox-Si-Nafion((R)) hybrid membranes show improvement in water retention and an increase in degradation temperature as identified by thermogravimetry analysis. Scanning electron micrographs reveal good dispersion of silica through the membrane. The fully hydrated Krytox-Si-Nafion((R)) hybrid membranes maintain their proton conductivity in a wide range of high temperatures (80-130 degrees C) in ambient condition of a closed system (without additional moisture feeding) as clarified by the plot of conductivity versus temperature. (c) 2006 Elsevier B.V All rights reserved.