We have employed deuteron nuclear magnetic resonance (NMR) spectroscopy in order to study the dynamics of the deuterated water (D2O) molecules introduced into a perfluorosulfonic acid ionomer Nafion (NR-211) film. According to the 2H NMR spectral analysis, the deuterated water molecules at low temperatures occupied either relatively rigid or mobile sites up to the temperature TM=240 K where all the deuterated water molecules became mobile. The temperature-dependent NMR linewidths sensitively reflected the motional narrowing of the rigid and mobile sites, and the NMR chemical shift reflected significant changes in the hydrogen bonds of the deuterated water. While a slow- to fast-limit motional transition was manifested at TM in the laboratory-frame NMR spin–lattice relaxation, the rotating-frame spin–lattice relaxation indicated no bulk liquid water state down to 200 K.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (Project no. 2013057555 , 2016R1D1A1A09917003, and NRF-2010-0027963 ). Measurements at the Korea Basic Science Institute (KBSI) are acknowledged.
- Lattice dynamics
- Nuclear magnetic resonance (NMR)
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics