Inorganic polymer based hybrid membranes consisting of zirconium oxide and polydimethylsiloxane (PDMS) have been synthesized by sol-gel processes. The organic/inorganic polymeric hybrid membranes showed thermal stability and flexibility up to 300 degreesC. The membrane becomes proton conducting polymer electrolyte when added with 12-phosphotungstic acid (PWA). The conductivity of the membranes was measured in the temperature range from room temperature to 150 degreesC under saturated humidity and a maximum conductivity of 5 x 10(-5) S cm(-1) was obtained at 150 degreesC. (C) 2003 Published by Elsevier Ltd.