Accession Number:
ADA263511
Title:
High Pressure Studies of Hydrated Nafion Membranes: Dielectric Relaxation and Deuteron NMR
Descriptive Note:
Interim technical rept. Mar 1992-Apr 1993
Corporate Author:
NAVAL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS
Personal Author(s):
Report Date:
1993-04-16
Pagination or Media Count:
16.0
Abstract:
Audio frequency electrical conductivitydielectric relaxation and nuclear magnetic resonance studies of Nafion-117 have been carried out at pressures up to 0.3 GPa 3 kbar. For some samples, the electrical conductivity exhibits dispersion typical of hopping conductivity in an amorphous material, sigmasigma o omega m. The values of m are sample dependent and vary from about 0.55 to 0.75. In addition, the values of m are not strongly pressure sensitive. At a given frequency, the electrical conductivity tends to decrease as pressure increases and yield activation volumes on the order of 5 to 10 cu. cmmol. The activation volume determined from the NMR spin-lattice relaxation time measurements are also sample dependent. The data shown correspond to an activation volume of about 8.6 cu.cmmol.
Descriptors:
- *DIELECTRICS
- *MEMBRANES
- *HYDRATION
- FREQUENCY
- MEASUREMENT
- VOLUME
- ACTIVATION
- HIGH PRESSURE
- MAGNETIC RESONANCE
- ELECTRICAL CONDUCTIVITY
- RESONANCE
- SULFONIC ACIDS
- AUDIO FREQUENCY
- DISPERSIONS
- SPIN STATES
- ION EXCHANGE
- FUEL CELLS
- LATTICE DYNAMICS
- RELAXATION TIME
- PRESSURE
- DEUTERONS
- FLUORINE
- PROTONS
- AMORPHOUS MATERIALS
- ELECTROCHEMISTRY
- NUCLEAR MAGNETIC RESONANCE
- WATER
- MATERIALS
Subject Categories:
- Inorganic Chemistry
- Physical Chemistry
- Electricity and Magnetism