Asymmetric orientation of toluene molecules at oil-silica interfaces

• Ledyastuti, Mia

• Liang, Yunfeng

• Kunieda, Makoto

• Matsuoka, Toshifumi

Abstract

The interfacial structure of heptane and toluene at oil-silica interfaces has previously been studied by sum frequency generation [Z. Yang et al., J. Phys. Chem. C.113, 20355 (2009)]10.1021/jp9043122. It was found that the toluene molecule is almost perpendicular to the silicasurface with a tilt angle of about 25°. Here, we have investigated the structural properties of toluene and heptane at oil-silica interfaces using molecular dynamics simulations for two different surfaces: the oxygen-bridging (hydrophobic) and hydroxyl-terminated (hydrophilic)surfaces of quartz (silica). Based on the density profile, it was found that both heptane and toluene oscillate on silicasurfaces, with heptane showing more oscillation peaks. Furthermore, the toluene molecules of the first layer were found to have an asymmetric distribution of orientations, with more CH[3] groups pointed away from the silicasurface than towards the silicasurface. These findings are generally consistent with previous experiments, and reveal enhanced molecular structures of liquids at oil-silica interfaces.

Journal

• Journal of Chemical Physics

  Journal of Chemical Physics 137 (6), 2012-08-09

  AIP Publishing

Details

• CRID: 1050564285747567616
• NII Article ID: 120005439711
• NII Book ID: AA00694991
• ISSN: 00219606
• HANDLE: 2433/187979
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles