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Detection of the Order-to-Disorder Transition in Block Copolymer Electrolytes Using Quadrupolar 7Li NMR Splitting
Lorena S Grundy, Gurmukh K Sethi, Michael D Galluzzo
1Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States.
Abstract:
The order-to-disorder transition temperature (TODT) in a series of mixtures of polystyrene-b-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is identified by the disappearance of a quadrupolar 7Li NMR triplet peak splitting above a critical temperature, where a singlet is observed. The macroscopic alignment of ordered domains required to produce a quadrupolar splitting occurs due to exposure to the NMR magnetic field. Alignment is confirmed using small-angle X-ray scattering (SAXS). The TODT determined by NMR is consistent with that determined using SAXS.
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