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Supercooling of water confined in reverse micelles

Spehr, T. and Frick, B. and Grillo, I. and Stühn, B. (2008):
Supercooling of water confined in reverse micelles.
In: Journal of Physics: Condensed Matter, p. 104204, 20, (10), ISSN 0953-8984, [Online-Edition: http://dx.doi.org/10.1088/0953-8984/20/10/104204],
[Article]

Abstract

We report on the temperature dependence of the nanosecond-timescale dynamics of the ternary mixture water/AOT/oil with deuterated heptane, toluene or decane as the oil. Water-swollen reverse micelles as formed in such microemulsions allow us to investigate the freezing behaviour of water confined in a soft environment. We report here on the first neutron scattering studies in which the freezing of the confined water and of the oil is followed down to temperatures at which the whole system is frozen. We focus on studies of water confined in three different droplet sizes: by means of small-angle neutron scattering we have determined the radii to be 46, 18, and 7 angstrom for water to surfactant ratios omega = 40, 12, and 3. From elastic temperature scans by neutron backscattering we deduce a strong supercooling of water confined in the reverse swollen micelles which increases with decreasing droplet size. For the smallest droplets we find a supercooling of more than 45 K compared to bulk water.

Item Type: Article
Erschienen: 2008
Creators: Spehr, T. and Frick, B. and Grillo, I. and Stühn, B.
Title: Supercooling of water confined in reverse micelles
Language: German
Abstract:

We report on the temperature dependence of the nanosecond-timescale dynamics of the ternary mixture water/AOT/oil with deuterated heptane, toluene or decane as the oil. Water-swollen reverse micelles as formed in such microemulsions allow us to investigate the freezing behaviour of water confined in a soft environment. We report here on the first neutron scattering studies in which the freezing of the confined water and of the oil is followed down to temperatures at which the whole system is frozen. We focus on studies of water confined in three different droplet sizes: by means of small-angle neutron scattering we have determined the radii to be 46, 18, and 7 angstrom for water to surfactant ratios omega = 40, 12, and 3. From elastic temperature scans by neutron backscattering we deduce a strong supercooling of water confined in the reverse swollen micelles which increases with decreasing droplet size. For the smallest droplets we find a supercooling of more than 45 K compared to bulk water.

Journal or Publication Title: Journal of Physics: Condensed Matter
Volume: 20
Number: 10
Divisions: 05 Department of Physics
05 Department of Physics > Institute for condensed matter physics
Date Deposited: 21 Dec 2009 14:22
Official URL: http://dx.doi.org/10.1088/0953-8984/20/10/104204
Additional Information:

4th European Conference on Neutron Scattering, Lund, Sweden, JUN, 2007

Identification Number: doi:10.1088/0953-8984/20/10/104204
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