INTERPRETATION OF SMALL-ANGLE X-RAY AND NEUTRON-SCATTERING DATA FOR PERFLUOROSULFONATED IONOMER MEMBRANES

This work gives credence to the thought that the small-angle scattering peak in ion-containing polymers is not a Bragg peak. This invalidates the conventional method of comparing the macroscopic and microscopic degrees of swelling. Previous SAXS work on dense groups of particles has neglected a term which is shown to be important at low angles. We found that this term is capable of qualitatively explaining the observed increase in intensity at low angles in perfluorosulfonated ionomers. The possibility of the presence of an intercluster potential, which can also contribute to the increase in intensity at these angles, is also discussed.