Spectroscopy of Nafion in terahertz frequency range.

We report results on the terahertz (THz) spectroscopy of polymer Nafion. Using THz pulse spectroscopy and refined post-processing algorithms based on the ill-posed spectroscopic inverse problem analysis, we find the complex dielectric permittivity of Nafion to be in the range 0.15-1.5 THz. The results in the low-frequency (gigahertz) range agree well with known measurements. We find that the complex dielectric permittivity can be described well using the double-Debye model with relaxation times of 7.20×0.05 ps and 0.12×0.05 ps. This result is discussed briefly from the viewpoint of the appearance of a segregated structure in the "Nafion-water" system. [ABSTRACT FROM AUTHOR]