Multistep thickening of nafion thin films in water

Yudai Ogata, Daisuke Kawaguchi, Norifumi L. Yamada, Keiji Tanaka

    Research output: Contribution to journalArticlepeer-review

    46 Citations (Scopus)


    Water sorption kinetics in thin Nafion films prepared on silver and silicon oxide substrates was examined by surface plasmon resonance and neutron reflectivity measurements. It was found that the films thickened in three regimes. The asymptotic swelling ratios in regimes I, II, and III were 1.05, 1.26, and 1.41, respectively. These values were independent of the substrate species and were coincident with the transition points of different hydration states in the bulk Nafion; water binding to sulfonic acid groups, the formation of sphere-like ionic clusters, and bridge formation between clusters. The swelling was much slower in thin films than in the bulk due to the mobility restriction of Nafion near the substrate.

    Original languageEnglish
    Pages (from-to)856-859
    Number of pages4
    JournalACS Macro Letters
    Issue number10
    Publication statusPublished - Oct 15 2013

    All Science Journal Classification (ASJC) codes

    • Organic Chemistry
    • Polymers and Plastics
    • Inorganic Chemistry
    • Materials Chemistry


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