Parallel cylindrical water nanochannels in Nafion fuel-cell membranes
Schmidt-Rohr, K; Qiang, C
| HERO ID | 618692 |
|---|---|
| In Press | No |
| Year | 2008 |
| Title | Parallel cylindrical water nanochannels in Nafion fuel-cell membranes |
| Authors | Schmidt-Rohr, K; Qiang, C |
| Journal | Nature Materials |
| Volume | 7 |
| Issue | 1 |
| Page Numbers | 75-83 |
| Abstract | The structure of the Nafion ionomer used in proton-exchange membranes of H2/O2 fuel cells has long been contentious. Using a recently introduced algorithm, we have quantitatively simulated previously published small-angle scattering data of hydrated Nafion. The characteristic ‘ionomer peak’ arises from long parallel but otherwise randomly packed water channels surrounded by partially hydrophilic side branches, forming inverted-micelle cylinders. At 20 vol% water, the water channels have diameters of between 1.8 and 3.5 nm, with an average of 2.4 nm. Nafion crystallites (∼10 vol%), which form physical crosslinks that are crucial for the mechanical properties of Nafion films, are elongated and parallel to the water channels, with cross-sections of ∼(5 nm)<sup>2</sup>. Simulations for various other models of Nafion, including Gierke’s cluster and the polymer-bundle model, do not match the scattering data. The new model can explain important features of Nafion, including fast diffusion of water and protons through Nafion and its persistence at low temperatures. [ABSTRACT FROM AUTHOR] Copyright of Nature Materials is the property of Nature Publishing Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts) |
| Doi | 10.1038/nmat2074 |
| Pmid | 18066069 |
| Wosid | WOS:000252117700024 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |
| Keyword | MEMBRANES (Technology); ALGORITHMS; IONOMERS; FUEL cells; PROTON exchange membrane fuel cells |
| Is Qa | No |