Water Uptake Profile In a Model Ion-Exchange Membrane: Conditions For Water-Rich Channels

Abstract

Ionic conductivity in a polymeric fuel cell requires water uptake. Previous theoretical studies of water uptake used idealized parameters. We report a parameter-free prediction of the water-swelling behavior of a model fuel cell membrane. The model polymers, poly(methyl- butylene)-block-poly(vinylbenzyl-trimethylamine) (PMB-b- PVBTMA), form lamellar do- mains that absorb water in humid air. We use the Scheutjens-Fleer methodology to predict the resulting change in lamellar structure and compare with x-ray scattering. The results suggest locally uniform water distributions. However, under conditions where a PVBTMA and water mixture phase-separate, the two phases arrange into stripes with a dilute stripe sandwiched between two concentrated stripes. A small amount of water enhances conductivity most when it is partitioned into such channels, improving fuel-cell performance.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 2014
Accession Number
ADA624943

Entities

People

  • Daniel C. Herbst

Organizations

  • Colorado School of Mines

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Alkenes
  • Block Copolymers
  • Chemical Elements
  • Computational Science
  • Differential Equations
  • Electrolytes
  • Energy
  • Equations
  • Equations Of State
  • Fuel Cells
  • Measurement
  • Military Research
  • Molecular Dynamics
  • Phase Separation
  • Random Walk
  • Three Dimensional
  • X Ray Scattering

Readers

  • Electrochemical Engineering/ Fuel Cell Technologies
  • Environmental Engineering
  • Optical Physics and Photonics.

Technology Areas

  • Biotechnology