Chitosan/PTFE composite membranes were prepared from casting a gamma-(glycidyloxypropyl)trimethoxysilane (GPTMS)-containing chitosan solution on poly(styrene sulfuric acid) grafted expended poly(tetrafluoroethylene) film surface. The adhesion between the chitosan skin layer and the PTFE substrate was pretty good to warrant the high performance of chitosan/PTFE composite membranes using in pervaporation dehydration processes on isopropanol. The chitosan/PTFE membrane exhibited a permeation flux of 1730 g/m(2) h and a separation factor of 775 at 70 degrees C on pervaporation dehydration of a 70 wt% isopropanol aqueous solution. The membrane also survived after a long-term operation test in 45 days. (c) 2006 Elsevier B.V. All rights reserved.