Nano Archive

Structure and dynamics of water confined in a boron nitride nanotube

Won, Chang Y. and Aluru, N. R. (2008) Structure and dynamics of water confined in a boron nitride nanotube. JOURNAL OF PHYSICAL CHEMISTRY C, 112 (6). pp. 1812-1818.

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Recent molecular dynamics simulations have shown that a finite-length (5,5) boron nitride nanotube (BNNT) in contact with an aqueous reservoir has superior water permeation properties compared to a (5,5) carbon nanotube of similar diameter and length. In this work, by using density functional theory (DFT), we compute the electrostatic potential arising from the weak ionic and covalent bonding of B-N. Quantum partial charges of B and N atoms, determined by matching the electrostatic potential computed by the DFT, are then included in molecular dynamics simulations to investigate the structure and dynamics of water confined in BNNTs of sizes ranging from (5,5) to (10,10). When partial charges are included, we observe that the wetting behavior of the (5,5) BNNT has improved and the single-file water chain in both (5,5) and (6,6) BNNTs has an L-defect. Further, with partial charges, except for a (9,9) BNNT which exhibits anomalous behavior, the diffusion coefficient of confined water molecules in (5,5), (6,6), and (10,10) BNNTs is found to decrease due to the formation of a hydrogen bond between water and nitrogen atoms. For a (9,9) BNNT, in the absence of partial charges, an ice-shell structure was observed with a critical slowing in the diffusion coefficient. When partial charges are included, the diffusion coefficient is found to increase because of the presence of an additional single-file water chain inside the ice-shell structure.

Item Type:Article
Subjects:Physical Science > Nano objects
Material Science > Nanochemistry
ID Code:2932
Deposited By:Anuj Seth
Deposited On:12 Jan 2009 15:08
Last Modified:20 Jan 2009 12:14

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