Photocrosslinking of Sulfonated Poly(arylene ether ketone)s in a Hydrated State to Obtain Proton Exchange Membranes with High Performance

Abstract

AbstractNovel sulfonated poly(arylene ether ketone)s (SCKs) containing photosensitive chalcone units in the main chain are synthesized by polycondensation of 4,4′‐dihydroxylchalcone, perfluorobiphenyl, and sodium 5,5′‐carbonyl bis(2‐fluorobenzenesulfonate). Photocrosslinking of SCK membranes in a hydrated state is implemented under UV irradiation, and characterization by UV–vis and X‐ray photoelectron spectroscopic techniques. The crosslinked structure formed in hydrated membranes endows crosslinked SCK membranes with desired properties, such as the greatly improved dimensional and chemical stabilities, relative better mechanical properties and thermal stability, without sacrificing proton conductivity of them. Proton conductivity of crosslinked SCK membranes only drops by 2.7–14%, and reaches 215 mS cm−1 at 80 °C, which is higher than that of Nafion117 (163 mS cm−1). Atomic force microscopy and small angle X‐ray scattering analysis verify that the photocrosslinked strategy of SCK membranes in a hydrated state could well preserve percolated hydrophilic channels in membranes and give crosslinked SCK membranes high performance desirable for proton exchange membrane.