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Proton-exchange-induced configuration rearrangement in a poly(ionic liquid) solution: a NMR study
journal contribution
posted on 2017-11-02, 00:00 authored by Haijin Zhu, Hengrui Yang, Jiaye Li, Kristine Barlow, Lingxue KongLingxue Kong, David Mecerreyes, Douglas R MacFarlane, Maria ForsythMaria ForsythPolymeric ionic liquids have emerged recently as a promising alternative to traditional polymers as the polymer electrolyte membrane materials of choice because of their strongly decoupled dynamics between the polymer backbone and the counterions. Knowledge of proton exchange and transport mechanism in such materials is critical to the design and development of new poly(ionic liquid) materials with improved electrochemical properties. Our NMR results show that the proton exchange between the labile proton of the diethylmethylammonium (NH122) cation and H2O molecules is accompanied by a concerted configuration rearrangement of the ammonium. Through a combination of PFG-NMR and proton relaxation (line width) analysis, we demonstrate that at lower temperatures the labile proton diffuses along with the NH122 ammonium cation as an integral unit, whereas at higher temperatures the NH/H2O proton exchange sets in gradually, and the PFG-NMR measured diffusion coefficient is a population-averaged value between the two exchanging sites.
History
Journal
Journal of Physical Chemistry LettersVolume
8Issue
21Pagination
5355 - 5359Publisher
American Chemical SocietyLocation
Washington, D.C.Publisher DOI
ISSN
1948-7185eISSN
1948-7185Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2017, American Chemical SocietyUsage metrics
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No categories selectedKeywords
Science & TechnologyPhysical SciencesTechnologyChemistry, PhysicalNanoscience & NanotechnologyMaterials Science, MultidisciplinaryPhysics, Atomic, Molecular & ChemicalChemistryScience & Technology - Other TopicsMaterials SciencePhysicsNUCLEAR-MAGNETIC-RESONANCETRANSPORT PHENOMENASELF-DIFFUSIONTRIFLIC ACIDWATERSYSTEMS
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