Lawler, Robin Caliendo, Charles Ju, Hyunchul Kim, Jin Young Lee, Seung Woo Jang, Seung Soon 2024-01-19T18:04:37Z 2024-01-19T18:04:37Z 2021-09-05 2020-02 1520-6106 https://pubs.kist.re.kr/handle/201004/119023 The effect of side-chain length on the nanophase-segregated structure and transport in perfluorinated sulfonic acid (PFSA)-based and perfluorinated phosphoric acid (PFPA)-based membranes is investigated at 20 and 5 wt % water content conditions using a molecular dynamics simulation method. It is found using the pair correlation analysis that the longer side chain leads to more developed local water structures in the water phase at 20 wt % water content, observable in both membrane chemistries albeit more distinct in PFPA-based membranes. It is also confirmed from the structure factor analysis that large-scale nanophase segregation is enhanced with increasing side-chain length for PFPA membranes, whereas no significant change is observed at these scales for PFSA membranes. Next, it is revealed that the proton transport is increased by 0.004 S/cm in PFSA-based membranes with increasing side-chain length due to the enhanced vehicular and hopping mechanisms, whereas the proton transport in PFPA-based membranes is decreased by 0.002 S/cm despite improved nanophase segregation. As confirmed by the pair correlation function analysis, the diminished proton transport in PFPA-based membranes is attributed to the molecular association of phosphate groups with hydronium ions via hydrogen bond in the longer side-chain case, which is namely a hydronium-mediated bridge configuration. Such bridge configurations and correspondingly similar trends in proton transport are also observed at 5 wt % water content condition to a lesser extent. Our simulation study demonstrates that the proton transport is affected by the hydrogen-bonding network as well as by the nanophase segregation. English AMER CHEMICAL SOC Effect of the Side-Chain Length in Perfluorinated Sulfonic and Phosphoric Acid-Based Membranes on Nanophase Segregation and Transport: A Molecular Dynamics Simulation Approach Article 10.1021/acs.jpcb.9b10408 1 JOURNAL OF PHYSICAL CHEMISTRY B, v.124, no.8, pp.1571 - 1580 JOURNAL OF PHYSICAL CHEMISTRY B 124 8 1571 1580 N scie scopus 000517672500022 2-s2.0-85080958296 Chemistry, Physical Chemistry Article POLYMER ELECTROLYTE MEMBRANES HYDROGEN-BOND LIFETIME FUEL-CELL TECHNOLOGY PROTON-TRANSFER EXCHANGE MEMBRANES IONOMER MEMBRANES PROTOGENIC GROUP FORCE-FIELD WATER NAFION