Accession Number : ADA616676


Title :   Anion Transport in a Chemically Stable, Sterically Bulky alpha-C Modified Imidazolium Functionalized Anion Exchange Membrane


Descriptive Note : Journal article


Corporate Author : COLORADO SCHOOL OF MINES GOLDEN


Personal Author(s) : Liu, Ye ; Wang, Junhua ; Yang, Yuan ; Brenner, Thomas M ; Seifert, Soeenke ; Yan, Yushan ; Liberatore, Matthew W ; Herring, Andrew M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a616676.pdf


Report Date : 24 Jun 2014


Pagination or Media Count : 13


Abstract : The morphology and anion transport of an alpha-C modified imidazolium functionalized anion exchange membrane, 1,4,5-trimethyl-2-(2,4,6-trimethoxyphenyl)imidazolium functionalized polyphenylene oxide (with ion exchange capacity {IEC} = 1.53 or 1.82 mequiv/g), were studied in detail. The novel cation is less susceptible to OH attack (0% degradation) compared to unsubstituted imidazolium functionalized polyphenylene oxide (25% degradation) after 24 h at 80 deg C in 1 M KOH. The two different IEC materials (with the same protected cation) show interesting differences in membrane performance. From AFM and SAXS under humid conditions, the domain sizes of the membrane change, which impact the transport properties. The lower IEC sample showed a smaller tortuosity and, thus, needs a longer diffusion time for the water molecules to be fully hindered inside the hydrophobic clusters, which is confirmed by water self-diffusion measurements from pulsed field gradient NMR. From conductivity and diffusion measurements, the higher IEC sample exhibited Vogel Tammann Fulcher behavior, thus indicating that the polymer chain s movement dominates the transport. However, the lower IEC sample exhibited the linear Arrhenius behavior signifying water-mediated transport. The maximum Cl conductivity observed was 23 mS/cm at 95% RH and 90 deg C.


Descriptors :   *ANIONS , *CHEMICAL STABILITY , *MEMBRANES , *TRANSPORT PROPERTIES , CONDUCTIVITY , FUEL CELLS , MORPHOLOGY


Subject Categories : Industrial Chemistry and Chemical Processing
      Physical Chemistry
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE