Temperature-dependent structure changes in Nafion ionomer studied by PCMW2D IR correlation spectroscopy

Temperature-dependent infrared (IR) spectra of a Nafion membrane were measured over a temperature range from 30 to 320 degrees C. The obtained spectra were analyzed using perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy and quantum chemical calculations (QCC). Three-step structural changes in Nafion ionomer induced by temperature were revealed. Dehydration of the ionomer is dominant below 60 degrees C. Protonation of sulfonate group in the side chain terminal occurs around 100 degrees C. Thermal degradation of the chains starts above 280 degrees C. (C) 2009 Elsevier B.V. All rights reserved.