Novel poly(arylene ether ketone) with fluorene pendants were synthesized and then sulfonated into a series of poly(arylene ether ketone)s with sulfonated fluorene pendants using chlorosulfonic acid. The sulfonated polymers were thereafter cast into membranes from their solutions. The properties of the ionic exchange capacity, sulfonation degree, water uptake, mechanical properties, thermal and oxidative stabilities as well as proton conductivities of the membranes were fully investigated. It was found that their proton conductivities increased continuously with increasing testing temperature up to 130 degrees C at 100% relative humidity. The membrane exhibited a higher proton conductivity and other comprehensive properties for proton exchange membrane than Natione- 117 at 130 degrees C under same testing conditions. (c) 2007 Elsevier B.V. All rights reserved.