Phase transitions of interfacial water at 165 and 240?K. Connections to bulk water physics and protein dynamics |
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Authors: | J-M Zanotti M C Bellissent-Funel A I Kolesnikov |
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Institution: | (1) Laboratoire Léon Brillouin (CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France;(2) IPNS, Argonne National Laboratory, Argonne, IL 60439, USA |
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Abstract: | We are considering water adsorbed as a monolayer on
Vycor, a porous silica glass. The interfacial water molecules interact with
the substrate through hydrogen bonding with the numerous silanol (Si-OH)
groups present all over the surface. This special form of water exhibits
peculiar dynamical properties. A combined calorimetric, diffraction, high
resolution quasi-elastic and inelastic neutron scattering study shows that
interfacial water experiences a glass transition at 165 K and a
liquid-liquid transition at 240 K from a low-density to a high
density-liquid. We show that this unusual behaviour, compared to the bulk,
is due to a strong weakening of the hydrogen-bond strength, possibly due to
the reduced number of hydrogen-bonds engaged by water molecules when they
are in an interfacial two dimensional situation. The connections of these
findings to the physics of bulk water and protein dynamics are discussed. |
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Keywords: | |
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