Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 64: Solid/liquid interfaces I (focussed session)

O 64.4: Vortrag

Donnerstag, 25. März 2010, 12:00–12:15, H33

Computation of the interfacial excess free energies of solid-liquid interfaces by molecular dynamics simulation and thermodynamic integration — •Frédéric Leroy and Florian Müller-Plathe — Eduard-Zintl-Institut für Physikalische und Anorganische Chemie, Technische Universität Darmstadt, Darmstadt, Germany

Solid-liquid interfacial tension is a key quantity in the thermodynamics of systems where a liquid is in the vicinity of a solid substrate. While fluid-fluid surface tensions have received a lot of attention, calculation of the solid-liquid interfacial tension is still an on-going task. We present an algorithm[1] that allows the computation of that quantity.

Rather than trying to compute an absolute interfacial free energy, we intend to obtain the free energy difference between the system where the liquid is interacting with the structured solid surface of interest and a reference system where the liquid is in contact with a flat surface, by performing thermodynamic integration from one system to the other. For example, the algorithm is useful in determining the change in free energy with respect to a modification of the chemical composition of the solid or a change in its topography.

We discuss the applications of the method in the frame of wetting in nano-scale systems and present its advantages through results dealing with Lennard-Jones model systems and water in interaction with graphite-based surfaces.

[1] F. Leroy, D.J.V.A. dos Santos and F. Müller-Plathe, Macromolecular Rapid Communications 2009, vol. 30, pp 864-870.