title: Effects of Block Length and Membrane Processing Conditions on the Morphology and Properties of Perfluorosulfonated Poly(arylene ether sulfone) Multiblock Copolymer Membranes for PEMFC.
abstract: Perfluorosulfonated poly(arylene ether sulfone) multiblock copolymers have been shown to be promising as proton exchange membranes. The commonly used approach for preparation of the membrane is solvent casting; the properties of the resulting membranes are very dependent on the membrane processing conditions. In this paper, we study the effects of block length, selectivity of the solvent, and thermal treatment on the membrane properties such as morphology, water uptake, and ionic conductivity. DiMethylSulfOxide (DMSO), and DiMethylAcetamide (DMAc) were selected as casting solvents based on the Flory-Huggins parameter calculated by inversion gas chromatography (IGC). It was found that the solvent selectivity has a mild impact on the mean size of the ionic domains and the expansion upon swelling, while it dramatically affects the supramolecular ordering of the blocks. The membranes cast from DMSO exhibit more interconnected ionic clusters yielding higher conductivities and water uptake as compared to membranes cast from DMAc. A 10-fold increase in proton conductivity was achieved after thermal annealing of membranes at 150 °C, and the ionomers with longer block lengths show conductivities similar to Nafion at 80 °C and low relative humidity (30%).
authors.affiliation: †Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble, France.|‡CNRS, LEPMI, F-38000 Grenoble, France.
authors.forename: Luca
authors.initials: L
authors.lastname: Assumma
authors.affiliation: †Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble, France.|‡CNRS, LEPMI, F-38000 Grenoble, France.
authors.forename: Huu-Dat
authors.initials: HD
authors.lastname: Nguyen
authors.affiliation: †Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble, France.|‡CNRS, LEPMI, F-38000 Grenoble, France.
authors.forename: Cristina
authors.initials: C
authors.lastname: Iojoiu
authors.affiliation: ⊥CEA-Grenoble, INAC/SPrAM, Groupe Polymères Conducteurs Ioniques, UMR-5819, CEA-CNRS-UJF, 17 Rue de Martyrs 38054 Grenoble, CEDEX 9 France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lyonnard
authors.affiliation: §Ingénierie des Matériaux Polymères, UMR-5223, IMP@LYON1, Université de Lyon, Université Lyon 1, 15 Bd. A Latarjet, 69622, Villeurbanne CEDEX France.
authors.forename: Régis
authors.initials: R
authors.lastname: Mercier
authors.affiliation: §Ingénierie des Matériaux Polymères, UMR-5223, IMP@LYON1, Université de Lyon, Université Lyon 1, 15 Bd. A Latarjet, 69622, Villeurbanne CEDEX France.
authors.forename: Eliane
authors.initials: E
authors.lastname: Espuche
keywords: PEMFC; block copolymer; membrane annealing; perfluorosulfonated aromatic ionomers; polymer electrolyte membrane; solvent selectivity