Sulfonated Oligomer‐crosslinked Fluorinated Poly(aryl ether sulfone)‐based Proton Exchange Membranes for Fuel Cells

Abstract

A series of sulfonated oligomer‐crosslinked fluorinated poly(aryl ether sulfone) membranes (c‐SPFAES) have been prepared in a consecutive casting and thermal treating process from fluorinated polymers and sulfonated oligomers, where the latter acted as hydrophilic grafts and crosslinkers at the same time. Membrane structure and physico‐chemical properties are characterized and evaluated by 1H‐nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and atomic force microscopy, Fenton, water‐swelling and H2/O2 single cell tests. For the c‐SPFAES membranes with ion exchange capacity of 1.04–1.78 mmol g−1, they exhibit excellent mechanical toughness with Young's moduli above 1.3 GPa and tensile strength beyond 35.8 MPa, good dimensional and thermo‐oxidative stability. They also exhibited clear hydrophilic‐hydrophobic phase‐separation morphology. The proton conductivity is higher than 0.1 S cm−1 for the c‐SPFAES membranes with IEC over 1.38 mmol g−1 at 60 °C. In a H2/O2 single cell test, the maximum power density of the c‐SPFAES‐1.61 membrane achieves 587 mW cm−2 at 80 °C under fully hydrated state. The c‐SPFAES membrane show promising potentials as a polymer electrolyte membrane candidate for fuel cell applications.

Preparation and Properties of Novel Cross‐Linked Fluorinated Poly(aryl ether) with Low Dielectric Constant and High Thermal Stability

“…In this study, we have successfully synthesized FPAE with reference to previous study. [ 30 ] 6FBPA react with decafluorobiphenyl (DFBP) in N , N ‐dimethylacetamide (DMAc) to gain the linear fluorinated FPAE with high molecular weight through nucleophilic substitution reaction at the moderate temperature of 80 °C. A slightly excessive (about 2%) of DFBP is used to avoid branching reactions or even cross‐linking reactions.…”

Cross‐Linked Fluorinated Poly(Aryl Ether) (C‐FPAE) Films: Preparation Strategy, Performance Study, and Low Dielectric Applications

“…The peaks at 7.05 and 7.4 ppm at Figure S1a (Supporting Information) are assigned to the radio-frequency radiation absorption of the hydrogen nucleus on phenylene, indicating that the synthesized FPAE in this study is consistent with the expected structure. In the 19 FNMR spectrum ( Figure S1b, Supporting Information), the peak "a" belongs to hexafluoroisopropyl groups and the peak "b" and peak "c" are attributed to the fluorine nucleus of DFBP moiety. The peak of F on the FPAE end group is not observed in the 19 FNMR spectrum ( Figure S1b, Supporting Information).…”

“…In the 19 FNMR spectrum ( Figure S1b, Supporting Information), the peak "a" belongs to hexafluoroisopropyl groups and the peak "b" and peak "c" are attributed to the fluorine nucleus of DFBP moiety. The peak of F on the FPAE end group is not observed in the 19 FNMR spectrum ( Figure S1b, Supporting Information). This is because the prepared FPAE has a large molecular weight, which causes the FPAE end group content to decrease in the system that it cannot be accurately detected by 19 FNMR.…”

Crosslinked quaternized poly(arylene ether sulfone) copolymer membrane applied in an electric double‐layer capacitor for high energy density

“…Various polymer matrixes, which determine the polymer electrolyte properties, have also been investigated; these include poly(vinylidene fluoride), poly(vinylidene fluoride‐ co ‐hexafluoropropylene), poly(vinyl alcohol), poly(ethylene oxide), polyacrylonitrile, Nafion, and poly(arylene ether) . Among these polymer matrixes, poly(arylene ether sulfone) (PAES) copolymers, a class of high‐performance amorphous thermoplastics with outstanding mechanical properties and thermal stabilities, have been widely used as substrate materials for proton or anion‐exchange membranes used in fuel cells and supercapacitors . However, quaternized PAES copolymers have generally been studied as substrate materials for separators used in alkaline electrolytes .…”