Exfoliation of Graphene in Ionic Liquids: Pyridinium versus Pyrrolidinium
Chaban, Vitaly V. [UNIFESP]
Fileti, Eudes Eterno [UNIFESP]
Prezhdo, Oleg V.
Is part ofJournal Of Physical Chemistry C
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Exfoliation is an elegant physical technique to directly obtain graphene from graphite. A search for high-performance exfoliation solvents is actively pursued nowadays. We report potentials of mean force and free energies, characterizing steered separation of graphene sheets and their subsequent solvation by room-temperature ionic liquids (RTILs). The exfoliation performance of N-butylpyriclinium bis(trifluoromethanestilfonyl)imide [BPY][TFSI] is compared to that of 1-butyl-1-methylpyrrolidinium bis(trifluoromethane-sulfonyl)imide [PYR] [TFSI]. Both RTILs are shown to exhibit comparable exfoliation performance, which is superior to the performance of 1-ethyl-3-methylimidazolium tetrafluoroborate by similar to 20 kJ mol(-1) nm(-1). The sulfur atom of TFSI- contributes an essential portion of the solvation enthalpy due to its dispersive attraction to carbon atoms of graphene. Both RTILs maintain a singlemoderately defined shell around the graphene surface. [BPY] [TFSI] and [PYR][TFSI] are suitable starting compounds to engineer more advanced solvents. The reported results support development of new higher-performance RTILs for use in solvent-assisted graphene exfoliation.
CitationJournal Of Physical Chemistry C. Washington, v. 121, n. 1, p. 911-917, 2017.
U.S. National Science Foundation
Photochemistry Center of the Russian Science Foundation
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