SAXS Analysis of the Thermal Relaxation Behavior of Oriented Perfluorosulfonate Ionomer Membranes

Published

August 1, 2002

Author(s)

Forrest A. Landis, R B. Moore, Kirt A. Page, Charles C. Han

Abstract

Small-angle X-ray scattering analysis has been performed on oriented samples of the Nafion perfluorosulfonate ionomer which have been neutralized with a variety of alkylammonium counterions. It has been shown that the temperature at which the oriented ionic domains within the ionomer begin to relax back to an isotropic state is dependent on the nature of the neutralizing cation. Nafion neutralized with the smaller tetramethylammonium counterion has a relaxtion temperature of greater than 250 degrees C. However, by systematically increasing the length of the alkyl groups on the alkylammonium counterion up to tetrabutyl, the temperature at which the SAXS analysis shows relaxation of the ionic aggregates shifts to lower temperatures. This effect is related to the decrease in the Coulombic forces between ion pairs as the size of the neutralizing counterion is increased allowing for thermally induced flow to occur.

Citation

Journal of the American Chemical Society

Volume

224

Pub Type

Journals

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Keywords

ion-hopping, ionomer, nation, orientation, X-ray scattering

Citation

Landis, F. , Moore, R. , Page, K. and Han, C. (2002), SAXS Analysis of the Thermal Relaxation Behavior of Oriented Perfluorosulfonate Ionomer Membranes, Journal of the American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852016 (Accessed October 20, 2025)