A series of fluorene-containing poly(arylene ether ketone)s were synthesized and sulfonated using chlorosulfonic acid and then were cast into membranes from their solutions. The ionic exchange capacity, sulfonatation degree, water-uptake properties, mechanical properties, thermal stabilities, and oxidative stabilities as well as conductivities were fully investigated. It was found that their conductivities increased continuously with the increasing of temperature up to 100 degrees C at 100% relative humidity. The proton conductivity of the membrane was determined to be close to that of Nafion-117 at 100 degrees C under the same testing conditions, together with the comprehensive properties for proton exchange membrane. (c) 2005 Elsevier B.V. All rights reserved.