Mechanical and transport properties of nafion: Effects of temperature and water activity

Jay Burton Benziger, Andrew Bruce Bocarsly, May Jean Cheah, Paul Majsztrik, Barclay Satterfield, Qiao Zhao

Research output: Chapter in Book/Report/Conference proceedingChapter

29 Scopus citations


Recent studies have shown that water absorption changes the mechanical and transport properties of Nafion by orders of magnitude. The unusually large changes in properties are indicative of microstructural changes induced by water absorption. The experimental findings of changes in proton conduction, water transport, elastic modulus, and stress relaxation are highlighted and explained by microphase segregation of hydrophilic domains resulting from water absorption. Water absorption is proposed to cause clustering of hydrophilic sulfonic acid groups and water within a hydrophobic polytetrafluoroethylene matrix. The hydrophilic domains form a network that facilitates transport and create physical cross-links that stiffen Nafion. At high temperature and low water activity, the entropy of de-mixing breaks the clusters apart, causing a large drop in elastic modulus of the polymer and a large decrease in the rates of water and proton transport.

Original languageEnglish (US)
Title of host publicationFuel Cells and Hydrogen Storage
EditorsAndrew Bocarsly, Michael Mingos
Number of pages29
StatePublished - 2011

Publication series

NameStructure and Bonding
ISSN (Print)0081-5993
ISSN (Electronic)1616-8550

All Science Journal Classification (ASJC) codes

  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry


  • Elastic modulus
  • Microphase separation
  • Stress relaxation
  • Thermal transitions


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