Proton transport property of nafion thin films on MgO(100) with anisotropic molecular structure

Abstract

To investigate the proton transport properties of the Nafion thin films on MgO(100) substrates, impedance measurements of the 60 and 400 nm thick thin films were carried out. The proton conductivity of two thin films were quite lower values compared to that of the commercial Nafion membrane, and the thickness dependence of the proton conductivity was also observed. To investigate in-plane and out-of-plane molecular vibrations in an identical 400 nm thick film of Nafion on the MgO(100) substrate, an infrared p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) technique was carried out. The in-plane spectrum showed well-known spectrum, however, the out-of-plane spectrum was quite different compared to the in-plane spectrum. The largely different shapes of the spectra clearly indicate that the 400 nm thick film of Nafion has an anisotropic molecular structure. © 2012 The Surface Science Society of Japan.