Designing Advanced Cross-Linked Proton Exchange Membranes with Enhanced Structural Homogeneity and Proton...

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Proton exchange membranes (PEMs) are critical for electrochemical devices.
• Existing PEMs often face challenges with structural homogeneity and chemical stability.
• Ethylene tetrafluoroethylene (ETFE) offers a cost-effective substrate for membrane fabrication.

Purpose of the Study:

• To develop well-defined, cross-linked PEMs using radiation-induced RAFT-mediated polymerization.
• To enhance the structural homogeneity and chemical stability of PEMs.
• To evaluate the proton conductivity of the novel cross-linked membranes.

Main Methods:

• Radiation-induced reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization.
• Grafting of polystyrene (PS) chains onto ETFE films followed by sulfonation.
• Characterization of membrane structure, chemical stability, and proton conductivity.

Main Results:

• Successful grafting of PS chains onto ETFE films and subsequent sulfonation.
• Cross-linking significantly improved chemical stability by approximately 4-fold.
• PEMs with 45% and 67% grafting exhibited high proton conductivity (93.7 and 139.1 mS cm⁻¹, respectively), outperforming Nafion.
• Enhanced structural homogeneity was achieved through the RAFT cross-linking process.

Conclusions:

• Radiation-induced RAFT-mediated polymerization is an effective method for creating well-defined, cross-linked PEMs.
• The developed PEMs demonstrate superior chemical stability and competitive proton conductivity.
• This approach offers a promising pathway for designing high-performance PEMs for various applications.