Accession Number:

ADA624943

Title:

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

Descriptive Note:

Doctoral thesis

Corporate Author:

COLORADO SCHOOL OF MINES GOLDEN

Personal Author(s):

Report Date:

2014-12-01

Pagination or Media Count:

83.0

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, polymethyl- butylene-block-polyvinylbenzyl-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.

Subject Categories:

  • Physical Chemistry
  • Electrochemical Energy Storage

Distribution Statement:

APPROVED FOR PUBLIC RELEASE