Structural Characterization and Physicochemical Properties of Functionally Porous Proton-Exchange Membrane Based on...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Proton-exchange membranes (PEMs) are critical components in fuel cells.
• Developing high-performance, cost-effective PEMs is an ongoing research challenge.
• Fluorinated polymers offer desirable properties for PEM applications.

Purpose of the Study:

• To synthesize and characterize novel fluorinated graft copolymers for PEM fuel cell applications.
• To investigate the morphology, physical properties, and electrochemical performance of the new membranes.
• To compare the properties of the developed membranes with commercial alternatives.

Main Methods:

• Free radical copolymerization of dehydrofluorinated polyvinylidene fluoride (D-PVDF), 3-sulfopropyl acrylate (SPA), and 1H, 1H, 2H-perfluoro-1-hexene (PFH).
• Characterization using small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), Scanning Electron Microscopy (SEM), and Differential Scanning Calorimetry (DSC).
• Electrochemical characterization including membrane area resistance and ionic conductivity measurements.

Main Results:

• Synthesized fluorinated PEMs with crystallinity degrees of 17% (PEM-RCF) and 16% (PEM-RCF-2).
• Observed crystallite grains of 5-6 nm and surface pores ranging from 20 to 140 nm.
• Achieved a lowest membrane area resistance of 0.9 Ωcm², comparable to Nafion® and CJMC membranes.
• Demonstrated electrochemical behavior consistent with commercial cation-exchange membranes.

Conclusions:

• The developed fluorinated graft copolymer PEMs show promising performance for fuel cell applications.
• The unique porous structure influences ionic conductivity, similar to track-etched membranes.
• These novel PEMs present a viable alternative to existing commercial cation-exchange membranes.