Water at nanoscale confined in single-walled carbon nanotubes studied by NMR

Ghosh, S and Ramanathan, KV and Sood, AK (2004) Water at nanoscale confined in single-walled carbon nanotubes studied by NMR. In: Europhysics Letters, 65 (5). pp. 678-684.

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Abstract

Proton NMR studies have been carried out as a function of temperature from 210K to 300K on water confined within single-walled carbon nanotubes. The NMR lineshape at and below the freezing point of bulk water is asymmetric and can be decomposed into a sum of two Lorentzians. The intensities of both the components decrease with the lowering of the temperature below 273K, one component,$L_1$, vanishing below 242K and the other component, $L_2$, below 217K . Following the simulations of Koga et al. showing that the radial density profile of confined water in single-wall carbon nanotubes has a distribution peak at the center which disappears below the freezing temperature, the $L-1$-component is associated with the protons of the water molecules at the center and the $L_2$-component is associated with protons of water molecules at a distance of ~3A from the walls of the nanotubes. In this scenario the complete freezing of the water at ~212K is preceded by the withdrawal of the water molecules from the center.

Item Type:	Journal Article
Publication:	Europhysics Letters
Publisher:	E D P Sciences
Additional Information:	The copyright of this article belongs to EDP Sciences.
Department/Centre:	Division of Chemical Sciences > Sophisticated Instruments Facility (Continued as NMR Research Centre) Division of Physical & Mathematical Sciences > Physics
Date Deposited:	09 Feb 2005
Last Modified:	19 Jan 2012 07:08
URI:	http://eprints.iisc.ac.in/id/eprint/2720

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