Accession Number:

ADA261505

Title:

Studies of Water in Nafion Membranes: Dielectric Relaxation and Deuteron and Oxygen-17 NMR

Descriptive Note:

Interim technical rept.

Corporate Author:

HUNTER COLL NEW YORK DEPT OF PHYSICS AND ASTRONOMY

Report Date:

1993-01-25

Pagination or Media Count:

38.0

Abstract:

Dielectric relaxation and both deuteron and oxygen-17 nuclear magnetic resonance measurements on NAFION-117 membranes with variable water content approx. 5 - 18 by weight are reported. Glassy behavior of the water domains at low T below approx. 200 K is evidenced by the specific nature of the observed dielectric loss peaks and 2 H NMR lineshapes. Activation energies extracted from 2 H spin-lattice relaxation data on the high T side of the T sub one minimum exhibit a steady increase with increasing water content. In spite of a high degree of water molecular mobility, angular-dependent spectra in both as- received and stretched samples reflect considerable anisotropy of the host polymer. A dielectric loss peak is observed which has previously been attributed to the glass transition of the aqueous domains.

Subject Categories:

  • Physical Chemistry
  • Polymer Chemistry
  • Crystallography
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE