This technology is a composite polymer membrane that forms a physical crosslinked structure through ionic interactions between a highly sulfonated poly(fluorenyl ether sulfone) (dsPFES) multiblock copolymer and an imidazolium-functionalized poly(ether sulfone) (imPES) random copolymer.
Perfluorinated polymer electrolyte membranes, such as Nafion, have high production costs and suffer from increased fuel crossover at temperatures above 80°C. While increasing the degree of sulfonation in hydrocarbon-based sulfonated polymers can improve ion conductivity, it often leads to excessive swelling, which compromises physical and chemical stability. Conversely, introducing chemical crosslinking typically results in reduced conductivity.
In this technology, imPES is added at 1–10 wt% relative to the weight of dsPFES to act as a crosslinking agent, enhancing the membrane's dimensional stability and chemical resistance while maintaining the ion channels created by the highly sulfonated structure. It achieves proton conductivity exceeding 0.24 S/cm at 80°C and can be manufactured simply through solution mixing and casting, without complex chemical crosslinking reactions. It is suitable for use as an electrolyte membrane for transport and portable PEMFCs, as well as in water treatment membranes like water filters, serving as a low-cost, high-performance alternative to perfluorinated membranes.
This invention was developed with support from the Ministry of Science, ICT and Future Planning for the development of high-performance anion exchange membrane source materials through molecular structure control.
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