@inproceedings{a98b158cc721457b873874e41706918a,
title = "Dielectric properties of polymer electrolyte membranes measured by two-port transmission line technique",
abstract = "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).",
author = "Z. Lu and M. Lanaganb and E. Manias and Macdonald, {D. D.}",
year = "2010",
doi = "10.1149/1.3502448",
language = "English (US)",
isbn = "9781607682059",
series = "ECS Transactions",
publisher = "Electrochemical Society Inc.",
number = "29",
pages = "95--105",
booktitle = "Electrochemical Engineering for the 21st Century (Dedicated to Richard C. Alkire)",
edition = "29",
}