| Autor: |
Singh, J. K., Kofke, D. A. |
| Zdroj: |
Langmuir; April 2005, Vol. 21 Issue: 9 p4218-4226, 9p |
| Abstrakt: |
We examine a model system to study the effect of pressure on the surface tension of a vapor−liquid interface. The system is a two-component mixture of spheres interacting with the square-well (A−A) and hard-sphere (B−B) potentials and with unlike (A−B) interactions ranging (for different cases) from hard sphere to strongly attractive square well. The bulk-phase and interfacial properties are measured by molecular dynamics simulation for coexisting vapor−liquid phases for various mixture compositions, pressures, and temperatures. The variation of the surface tension with pressure compares well to values given by surface-excess formulas derived from thermodynamic considerations. We find that surface tension increases with pressure only for the case of an inert solute (hard-sphere A−B interactions) and that the presence of A−B attractions strongly promotes a decrease of surface tension with pressure. An examination of density and composition profiles is made to explain these effects in terms of surface-adsorption arguments. |
| Databáze: |
Supplemental Index |
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