Fumed-silica-filled polydimethylsiloxane (PDMS)-polyamide (PA) composite membranes were prepared by the introduction of hydrophobic fumed silica into a PDMS skin layer. The cross-sectional morphology of these filled composite membranes was observed with scanning electron microscopy. Their pervaporation performances were tested with aqueous ethanol solutions at 30, 35, and 40 degrees C. Increasing the amount of the fumed silica resulted in significantly enhanced ethanol permeability of the membranes. When the content of the fumed silica in the PDMS skin layer was 20 wt %, the ethanol permeability increased to nearly twice that of the unfilled PDMS-PA composite membrane. (C) 2007 Wiley Periodicals, Inc.