Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Hydrolysis of the Nafion® precursor studied by X-ray scattering and in-situ atomic force microscopy

Hydrolysis of the Nafion® precursor studied by X-ray scattering and in-situ atomic force microscopy AbstractThe hydrolysis of Nafion® † precursor material to a perfluorosulfonate ion exchange membrane has been studied in situ at the surface of a sample using atomic force microscopy (AFM), and in the bulk using a combination of small and wide-angle X-ray scattering. The AFM results show that there is a rapid and significant change in the surface morphology of the sample during the first 12 min after the introduction of aqueous hydroxyl ions, provided that an appropriate swelling agent is used. After this point there is little change in surface morphology, although bulk swelling of the sample continues. The wide-angle X-ray scattering results indicate a significant drop in the degree of crystallinity of fluorocarbon matrix from 14±1% to 7±1% on hydrolysis, as a result of the bulk structural reordering necessary to accommodate the formation of ionic clusters. Ionic clustering is confirmed by the appearance of a characteristic small-angle X-ray peak. However, the peak forms towards the end of the hydrolysis process, and subsequently coarsens, suggesting that the formation of ionic clusters is a slow process compared to the rate of hydrolysis. It is confirmed that an appropriate water/solvent mixture is necessary to achieve an efficient conversion of precursor to membrane. AFM images of the precursor surface, when water alone is used, show no signs of structural change. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png e-Polymers de Gruyter

Hydrolysis of the Nafion® precursor studied by X-ray scattering and in-situ atomic force microscopy

Loading next page...
 
/lp/de-gruyter/hydrolysis-of-the-nafion-precursor-studied-by-x-ray-scattering-and-in-HrStR7JJmg
Publisher
de Gruyter
Copyright
© 2013 by Walter de Gruyter GmbH & Co.
ISSN
2197-4586
eISSN
1618-7229
DOI
10.1515/epoly.2001.1.1.210
Publisher site
See Article on Publisher Site

Abstract

AbstractThe hydrolysis of Nafion® † precursor material to a perfluorosulfonate ion exchange membrane has been studied in situ at the surface of a sample using atomic force microscopy (AFM), and in the bulk using a combination of small and wide-angle X-ray scattering. The AFM results show that there is a rapid and significant change in the surface morphology of the sample during the first 12 min after the introduction of aqueous hydroxyl ions, provided that an appropriate swelling agent is used. After this point there is little change in surface morphology, although bulk swelling of the sample continues. The wide-angle X-ray scattering results indicate a significant drop in the degree of crystallinity of fluorocarbon matrix from 14±1% to 7±1% on hydrolysis, as a result of the bulk structural reordering necessary to accommodate the formation of ionic clusters. Ionic clustering is confirmed by the appearance of a characteristic small-angle X-ray peak. However, the peak forms towards the end of the hydrolysis process, and subsequently coarsens, suggesting that the formation of ionic clusters is a slow process compared to the rate of hydrolysis. It is confirmed that an appropriate water/solvent mixture is necessary to achieve an efficient conversion of precursor to membrane. AFM images of the precursor surface, when water alone is used, show no signs of structural change.

Journal

e-Polymersde Gruyter

Published: Dec 1, 2001

There are no references for this article.