Multiblock copolymers with highly sulfonated blocks containing di- and tetrasulfonated arylene sulfone segments for proton-exchange membrane fuel cell applications

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Abstract

Multiblock copoly(arylene ether sulfone)s with different block lengths and ionic contents are tailored for highly stable and proton conducting electrolyte membranes. Two series of fully aromatic copolymers are prepared by coupling reactions between non-sulfonated hydrophobic precursor blocks and highly sulfonated hydrophilic precursor blocks containing either fully disulfonated diarylsulfone or fully tetrasulfonated tetraaryldisulfone segments. The sulfonic acid groups are exclusively introduced in ortho positions to the sulfone bridges to impede desulfonation reactions, and give the blocks ion exchange capacities (IECs) of 4.1 and 4.6 meq./g, respectively. Solvent cast block copolymer membranes show well-connected hydrophilic nanophase domains for proton transport and high decomposition temperatures above 310 ˚C under air. Despite higher IEC values, membranes containing tetrasulfonated tetraaryldisulfone segments display a markedly lower water uptake than the corresponding ones with disulfonated diarylsulfone segments when immersed in water at 100 ˚C, presumably because of the much higher chain stiffness and glass transition temperature of the former segments. The former membranes have proton conductivities in level of a perfluorosulfonic acid membrane (NRE212) under fully humidified conditions. A membrane with an IEC of 1.83 meq./g reaches above 6 mS/cm under 30% relative humidity at 80 ˚C, to be compared with 10 mS/cm for NRE212 under the same conditions.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Sciences

Keywords

  • ionomer, block copolymer, polyelectrolyte, sulfonation, polycondensation, water transport, fuel cell membrane
Original languageEnglish
Pages (from-to)129-140
JournalAdvanced Energy Materials
Volume2
Issue number1
Publication statusPublished - 2012
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Polymer and Materials Chemistry (LTH) (011001041)