Understanding Aqueous Dispersibility of Boron Nitride Nanosheets from H-1 Solid State NMR and Reactive Molecular Dynamics

Arunachalam, Vaishali and Vasudevan, Sukumaran (2018) Understanding Aqueous Dispersibility of Boron Nitride Nanosheets from H-1 Solid State NMR and Reactive Molecular Dynamics. In: JOURNAL OF PHYSICAL CHEMISTRY C, 122 (8). pp. 4662-4669.

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Abstract

Stable aqueous dispersions of BN nanosheets can be obtained by the sonication assisted exfoliation of hexagonal BN powders in water without the need of stabilizers: a phenomenon not observed for the isoelectronic graphite, of comparable hydrophobicity. We show here that the aqueous dispersions are stabilized by electrostatic repulsive interactions and establish from zeta potential measurements that the BN nanosheets are positively charged on delamination with the medium turning increasingly basic as sonication proceeds. We have investigated how charge develops on the sheets by reactive force-field (ReaxFF) molecular dynamics simulations of the interaction of water with BN nanosheets and independently identified the major chemical species present on the nanosheets from H-1 and B-11 solid-state NMR measurements. Charges develop on the sheets as a consequence of the dissociation of water molecules at the edges of the sheet that leave the nitrogen edge atoms protonated and the release of hydroxyl groups into the bulk leading to an increased basicity of the medium.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY C
Publisher:	Department of Science and Technology, Government of India
Additional Information:	Copy right for the article belong to Department of Science and Technology, Government of India
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	12 Apr 2018 18:49
Last Modified:	12 Apr 2018 18:49
URI:	http://eprints.iisc.ac.in/id/eprint/59529

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