Dielectric properties of polymer electrolyte membranes measured by two-port transmission line technique

Z. Lu, M. Lanaganb, E. Manias, D. D. Macdonald

Research output: Chapter in Book/Report/Conference proceedingConference contribution

11 Scopus citations


The microwave dielectric properties of perfluorosulfonic acid membranes are characterized by a two-port transmission line technique. Two dielectric relaxation modes are observed in the microwave region (0.045-26 GHz) at 25°C The higher frequency process observed is identified as the cooperative relaxation of bulk-like water, whose amount was found to increase linearly with water content in the polymer. The lower-frequency process, characterized by longer relaxation times in the range of 20-70 picoseconds, is attributed to water molecules that are loosely bound to sulfonate groups. The loosely bound water amount was found to increase with hydration level at low water content, and levels-off at higher water contents. Flemion SH150, which has an equivalent weight of 909 g/equiv, displays higher dielectric strengths for both of these water modes compared to Nafion 117 (equivalent weight of 1100 g/equiv).

Original languageEnglish (US)
Title of host publicationElectrochemical Engineering for the 21st Century (Dedicated to Richard C. Alkire)
PublisherElectrochemical Society Inc.
Number of pages11
ISBN (Electronic)9781566778558
ISBN (Print)9781607682059
StatePublished - 2010

Publication series

NameECS Transactions
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

All Science Journal Classification (ASJC) codes

  • Engineering(all)


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