APS » PROLA » Phys. Rev. Lett. » Volume 79 » Issue 26

Phys. Rev. Lett. 79, 5262 - 5265 (1997)

Freezing of Confined Water: A Bilayer Ice Phase in Hydrophobic Nanopores
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Kenichiro Koga1, X. C. Zeng1, and Hideki Tanaka2
1Department of Chemistry and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588
2Department of Polymer Chemistry, Kyoto University, Kyoto, 606-01 Japan

Received 30 July 1997

Molecular dynamics simulations were performed to study the phase behavior of a thin film of water confined to a slit nanopore with smooth walls. A first-order water-to-ice freezing transition has been observed. The resulting ice, which is a crystal of bilayer consisting of rows of distorted hexagons, does not resemble any ice crystals found so far. The confined water contracts upon freezing when the confinement load is low ( ∼0.5 kbar) and expands when the load is high (10 kbar). The residual entropy of the bilayer ice can be calculated exactly, which is about half of the entropy of the bulk ice.


©1997 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v79/p5262
DOI: 10.1103/PhysRevLett.79.5262
PACS: 61.20.Ja, 61.20.Qg, 68.15.+e, 92.40.Sn

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