Eur. Phys. J. E (2003) 12: 131-134
https://doi.org/10.1140/epjed/e2003-01-030-4

Characterization of porous structure through the dynamical properties of ions confined in sulfonated polyimide ionomers films

¹ Groupe des Polymères Conducteurs Ioniques, SI3M/DRMFC/CEA-Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9, France
² Laboratoire de Spectrométrie Physique, CNRS-LSP/UMR C5588-Université J. Fourier, B.P. 87, 38402 Saint-Martin d’Hères, France
³ Centre de Recherche sur la Matière Divisée, CNRS-Université d’Orléans, 45071 Orléans Cedex 2, France
⁴ Centre de Recherche sur les Matériaux à Hautes Températures, CNRS UPR4212, 1D avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France

^* e-mail: rollet@cnrs-orleans.fr

Received: 1 January 2003
Published online: 5 November 2003

Abstract

The structure of sulfonated PolyImide (sPI) ionomer membrane has been investigated via the transport properties of ions confined inside. Transport coefficients of N(CH₃)₄ ⁺ and Na⁺ ions have been determined by several techniques in order to get a range of time/space scale as wide as possible: a method using radiotracers, conductivity, pulsed field gradient NMR and NMR quadrupolar relaxation rates determination. For N(CH₃)₄ ⁺, the self-diffusion has been measured in the direction of membrane plan (parallel) and in the perpendicular direction (transverse), whereas for Na⁺ only transverse self-diffusion has been measured. The conductivity of both ions has been measured in the transverse direction. The results show a anisotropic and multiscale structure with a separation phase between hydrophilic and hydrophobic domains that is not well-defined.