Document Type

Article

Publication Date

2005

Publication Title

Journal of the Electrochemical Society

Abstract

A thermodynamic model is proposed to describe the sorption of water in Nafion based on the Flory-Huggins activity model and an appropriate osmotic pressure correction term for the chemical potential of water within the swollen membrane. The key variables for sorption are equivalent weight of ionomer, acid strength of the ionic groups, modulus of polymer elasticity, and interaction between water and polymer. The water uptake per unit mass of dry Nafion increases with the increasing acid strength of the functional groups, decreasing Young’s modulus, and decreasing equivalent weight of Nafion. The model provides insights into the sorption and swelling behavior of ion-exchange membranes, and thus, may be useful in evaluating and designing alternate proton-exchange membranes for fuel cell applications. In a companion paper (Part II), a predictive model is presented for the transport of protons in Nafion.

Volume

152

Issue

3

First Page Number

E84

Last Page Number

E89

DOI

10.1149/1.1855872

Publisher Statement

© The Electrochemical Society, Inc., 2005. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in Journal of the Electrochemical Society 152 (3), E84-E89.

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