Understanding Water Uptake and Transport in Nafion Using X-ray Microtomography.

ACS Macro Lett

Environmental Energy Technologies Division and Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, United States.

Published: April 2013

To develop new ionomers and optimize existing ones, there is a need to understand their structure/function relationships experimentally. In this letter, synchrotron X-ray microtomography is used to examine water distributions within Nafion, the most commonly used ionomer. Simultaneous high spatial (∼1 μm) and temporal (∼10 min) resolutions, previously unattained by other techniques, clearly show the nonlinear water profile across the membrane thickness, with a continuous transition from dynamic to steady-state transport coefficients with the requisite water-content dependence. The data also demonstrate the importance of the interfacial condition in controlling the water profile and help to answer some long-standing debates in the literature.

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http://dx.doi.org/10.1021/mz300651aDOI Listing

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