Percolation in S-SEBS and Fluorocarbon Proton Conducting Membranes
Abstract
Electrical conductivity results at a variety of pressures, temperatures and water contents are evaluated for sulfonates styrene/ethylene-butylene/styrene (S-SEBS) triblock polymer, Nafion 117, and Dow 800 proton conducting membranes. In addition, room temperature and atmospheric pressure diffusion coefficients determined from conductivity and H-1 pulsed gradient spin-echo nuclear magnetic resonance (NMR) studies are considered. While the S-SEBS and fluorocarbons exhibit a percolation threshold at 10 and 4 wt-%, respectively, all materials exhibit this phenomenon at a volume water fraction of C approx. 0.035. Above the threshold the conductivity exhibits a power law behavior. When the volume of the hydrophobic portion of the membrane is subtracted the threshold occurs at the adjusted volume fraction of C(A) approx. 0. 12 which approaches that expected for continuum percolation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2000
- Accession Number
- ADA379724
Entities
People
- C. A. Edmondson
- John J. Fontanella
Organizations
- United States Naval Academy