title: Spatial and temporal mapping of water content across Nafion membranes under wetting and drying conditions.
abstract: Water transport and water management are fundamental to polymer electrolyte membrane fuel cell operation. Accurate measurements of water content within and across the Nafion layer are required to elucidate water transport behavior and validate existing numerical models. We report here a direct measurement of water content profiles across a Nafion layer under wetting and drying conditions, using a novel magnetic resonance imaging methodology developed for this purpose. This method, multi-echo double half k-space spin echo single point imaging, based on a pure phase encode spin echo, is designed for high resolution 1D depth imaging of thin film samples. The method generates high resolution (<8 microm) depth images with an SNR greater than 20, in an image acquisition time of less than 2 min. The high temporal resolution permits water content measurements in the transient states of wetting and drying, in addition to the steady state.
authors.affiliation: MRI Centre, Department of Physics, University of New Brunswick, Post Office Box 4400 I.U.C., Fredericton, NB, Canada E3B 5A3.
authors.forename: Ziheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Marble
authors.forename: Bryce
authors.initials: B
authors.lastname: MacMillan
authors.forename: Keith
authors.initials: K
authors.lastname: Promislow
authors.forename: Jonathan
authors.initials: J
authors.lastname: Martin
authors.forename: Haijiang
authors.initials: H
authors.lastname: Wang
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Balcom
mesh_terms: D000042:Absorption; D000465:Algorithms; D003198:Computer Simulation; D003890:Desiccation / Q000379:methods*; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008567:Membranes, Artificial; D008956:Models, Chemical; D014867:Water / Q000032:analysis* / Q000737:chemistry*
chemical_list: D005465:Fluorocarbon Polymers; D008567:Membranes, Artificial; D014867:Water; C040402:perfluorosulfonic acid