Proton conducting electrolyte membranes based on the pendant-sulfonated poly(arylene ether ketone)/polyorganosiloxane interpenetrating polymer networks

► Proton-conducting membranes were prepared in semi-IPN structure. ► Membranes exhibited superior proton conductivity but similar methanol permeability to the pristine SPEEK. ► The water uptake increased only to 64% as the OSPN content was increased to 50%, even at 80 °C. ► Power density was enhanced with increasing OSPN content up to 50 wt%.