Two-dimensional supercritical behavior of an ethanol monolayer: A molecular dynamics study

Yoshimichi Andoh, Kenji Yasuoka

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The two-dimensional (2D) supercritical behavior of an ethanol monolayer formed at the vapor/liquid interface of an ethanol solution has been investigated by a molecular dynamics (MD) calculations with a combination of the OPLS-UA and SPC/E potential models. A 100 Å thick slab of ethanol solution was placed at the volume center of the rectangular unit cell by 10 Å thick nonabsorbate water surfaces. With such an initial configuration, five independent 15 ns NVT constant MD calculations were carried out under 298.15 K, in which the initial ethanol mole fraction of the bulk solution layer χethint was set to 0.010, 0.022, 0.045, 0.10, and 0.20, respectively. The 2D radial distribution function (rdf) of an adsorbed ethanol molecule showed that the ethanol monolayer could be regarded as a 2D fluid where the adsorbed ethanol molecule had an effective 2D diameter of 4.65 Å. On the basis of the 2D rdf result, 2D cluster analysis was carried out from the perspective of the percolation theory. It is confirmed that the critical area occupation probability density, the critical exponents, and the fractal dimension of both nonpercolating and percolating clusters satisfied their nature of universality. Therefore, we concluded that an ethanol monolayer formed at the vapor/liquid interface of ethanol solution behaves as a 2D supercritical fluid at 298.15 K.

Original languageEnglish
Pages (from-to)10885-10894
Number of pages10
JournalLangmuir
Volume21
Issue number23
DOIs
Publication statusPublished - 2005 Nov 8

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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