Graphene-Solvent Interactions in Nonaqueous Dispersions: 2D ROESY NMR Measurements and Molecular Dynamics Simulations

Arunachalam, Vaishali and Vasudevan, Sukumaran (2018) Graphene-Solvent Interactions in Nonaqueous Dispersions: 2D ROESY NMR Measurements and Molecular Dynamics Simulations. In: JOURNAL OF PHYSICAL CHEMISTRY C, 122 (3). pp. 1881-1888.

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Abstract

The liquid phase exfoliation of graphite by sonication in nonaqueous solvents like N-methyl-2-pyrrolidone (NMP) provides a simple and scalable route to dispersions of defect-free graphene sheets. The role of the solvent is crucial to the process; it is the interactions of the solvent with the graphene sheets that prevent agglomeration and stabilize the dispersion. Here, we show that the two-dimensional solution nuclear magnetic resonance (NMR) technique, rotating frame Overhauser effect spectroscopy (ROESY), provides a molecular signature of these interactions in graphene NMP dispersions. Significant differences are observed in the spectra of the dispersions as compared to the pure solvent. Using classical molecular dynamics simulations, we show that these differences arise because of the induced layering of solvent molecules with reduced rotational mobility in the vicinity of the graphene sheets. The reduced mobility of solvent molecules in the dispersion as compared to the bulk solvent are reflected as differences in their two-dimensional ROESY NMR.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY C
Additional Information:	Copy right for this article belong to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	02 Mar 2018 14:56
Last Modified:	02 Mar 2018 14:56
URI:	http://eprints.iisc.ac.in/id/eprint/59048

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