UV-crosslinked poly(arylene ether sulfone) - LAPONITE ® nanocomposites for proton exchange membranes

The dimensional stability and barrier properties of proton exchange membranes are critical issues for high-performance proton exchange membrane fuel cells (PEMFCs). In this work, we introduce a viable and effective strategy for preparing high proton-conductive polymer membranes with remarkable dimensional stability and barrier properties. Sulfonated poly(arylene sulfone)s (sPASs) with a UV-crosslinkable monomer, 2,2 '-diallylbisphenol A (DABPA), is successfully synthesized via condensation polymerization, showing competitive molecular weights and sulfonation degrees to the neat polymer. Crosslinked nanocomposite membranes can be fabricated by incorporating soft bridge molecules and exfoliated LAPONITE (R) nanofillers, and subsequent UV-crosslinking. The sPAS-LAPONITE (R) nanocomposite membranes show greatly improved dimensional stabilities and barrier properties including remarkably reduced swelling ratio in solvent or methanol aqueous solutions. These enhanced properties lead to excellent performance in a direct methanol fuel cell (DMFC) test, surpassing that of a commercially available Nafion membrane based devices.