We have employed impedance spectroscopy in order to study the intrinsic dielectric properties and dynamics of a perfluorosulfonic acid ionomer Nafion (NR-211) membrane. Distinct dielectric relaxation processes involving ionic and chain motions were elucidated by using a frequency-temperature contour plot analysis of the dielectric loss. Furthermore, the low-frequency dielectric loss data that reflect the fractal chain structure of the Nafion system indicated the least topological imperfection of the ionic clusters at the temperature of the maximum loss tangent, Tg = 325 K. An equivalent circuit analysis of the complex impedance manifested a drastic motional slowing down that was apparently associated with a relaxation process around Tg.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (Project No. 2016R1D1A1A 09917003). The measurements at the Korean Basic Science Institute (KBSI) are acknowledged. J.H.H. acknowledges financial support from KBSI grant (D36611) funded by the KBSI.
© 2018, The Korean Physical Society.
- Dielectric relaxation
- Impedance spectroscopy
- Nafion membrane
ASJC Scopus subject areas
- Physics and Astronomy(all)