POS6-0453
Enhanced Low-Humidity Performance of Block Copolymer-Based Composite Proton Exchange Membranes
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Seonwoo Yang (Korea Advanced Institute of Science and Technology)
Co-Author(s)
Abstract
Attributed to their perfluorinated backbone, perfluoroalkyl sulfonic acid (PFSA) proton exchange membranes (PEMs) exhibit exceptional stability and performance. However, high costs and increasing environmental regulations raise the demand for hydrocarbon-based PEMs. For now, most hydrocarbon PEMs suffer from severe dehydration and dramatic conductivity loss under low-humidity fuel cell operations due to proton channel collapse. In this study, we present a composite proton exchange membrane by impregnating a hydrocarbon-based triblock copolymer, PS-b-P(SSA-co-DS)-b-PS synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization, into a porous ePTFE substrate. The spatial confinement within the ePTFE matrix induces severe geometric frustration, disrupting long-range ordering to form a highly interconnected and tortuous 3D continuous proton-conducting network. Furthermore, the high tortuosity within the proton channel, combined with internal hydrophobic DS struts, create physical bottlenecks smaller than 5 nm. This unique architecture thermodynamically triggers capillary condensation, securely trapping water within the membrane. Consequently, the synthesized composite membrane successfully prevents the collapse of proton pathways, exhibiting in-plane dimensional stability and superior fuel cell performance compared to Nafion even under harsh conditions (e.g., 20% RH).
