We have employed proton nuclear magnetic resonance (NMR) spectroscopy in order to study the low-temperature water dynamics in a water-soaked perfluorosulfonic acid ionomer Nafion (NR-211) film. According to the recent models, Nafion may comprise water strongly bound to the sulfonic acid group, hydration water, and condensed water species. In this work, three separate NMR peaks from the water species revealing distinct behaviors were identified. A significant portion of the ”bound” water remained unfrozen down to 200 K, whereas a slow-to-fast motional limit transition was observed at TM=220 K from the relaxation measurements.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (Project Nos. 2016R1D1A1A09917003 and NRF-2010-0027963). Measurements at the Korea Basic Science Institute (KBSI) are acknowledged. J.H.H. acknowledges financial support from KBSI grant ( D36611 ) funded by the Korea Basic Science Institute (KBSI) .
© 2016 Elsevier Ltd
- A. Water-soaked Nafion film
- D. Non-freezing water dynamics
- E. Proton nuclear magnetic resonance spectroscopy
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- Materials Chemistry