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) : McLin, M G ; Wintersgill, M C ; Fontanella, J J ; Chen, R S ; Jayakody, J P ; Greenbaum, S G


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a263511.pdf


Report Date : 16 Apr 1993


Pagination or Media Count : 16


Abstract : Audio frequency electrical conductivity/dielectric 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, sigma=sigma 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. cm/mol. 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.cm/mol.


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


Distribution Statement : APPROVED FOR PUBLIC RELEASE