State of water in nafion 117 proton exchange membranes studied by dielectric relaxation spectroscopy

Georgios Polizos, Zijie Lu, Digby D. Macdonald, Evangelos Manias

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

The dynamics and the nature of water environments in a fuel cell proton exchange membrane are studied experimentally. Specifically, the dynamics of water in Nafion 117 membranes, in the acid form, were investigated at two hydration levels and several temperatures by means of dielectric relaxation spectroscopy; two different dielectric spectroscopy experimental setups were employed for low (10-2-107 Hz, 25 to -80°C) and microwave (0.045-26 GHz, 35°C) frequency ranges. Three states of water were clearly identified: (a) water strongly bound to the sulfonic groups (in quantitative agreement with previous investigations) defining the first hydration layer; (b) loosely bound water, surrounding the first layer, and (c) free water, having similar dynamics as in the bulk/liquid water. This is the first time that the dynamics of loosely bound water are experimentally observed.

Original languageEnglish
Title of host publicationSolid-State Ionics-2006
Pages131-136
Number of pages6
StatePublished - 2007
Externally publishedYes
Event2006 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 27 2006Dec 1 2006

Publication series

NameMaterials Research Society Symposium Proceedings
Volume972
ISSN (Print)0272-9172

Conference

Conference2006 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston, MA
Period11/27/0612/1/06

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