Retraction to “Synthesis and characterization of a novel sulfonated poly (aryl ether ketone sulfone) semi-crosslinked membrane with high proton selectivity through click reaction for direct methanol fuel cells”

Retraction to “Synthesis and characterization of a novel sulfonated poly (aryl ether ketone sulfone) semi-crosslinked membrane with high proton selectivity through click reaction for direct methanol fuel cells”