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Perfect wetting along a three-phase line: theory and molecular dynamics simulations
1Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Consejo Superior de Investigaciones Científicas, Campus de la Universitat Autónoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. amejia@icmab.es
The Journal of Chemical Physics
|July 11, 2006
Summary
Density Gradient Theory (DGT) and molecular dynamics simulations reveal permanent perfect wetting in type-II Lennard-Jones mixtures. These simulations confirm a stable three-phase equilibrium across all explored thermodynamic conditions.
Area of Science:
- Physical Chemistry
- Thermodynamics
- Materials Science
Background:
- Understanding wetting phenomena is crucial for predicting fluid behavior at interfaces.
- Type-II mixtures exhibit complex phase equilibria, including three-phase coexistence.
- Accurate theoretical models and simulation methods are needed to describe these systems.
Purpose of the Study:
- To investigate the wetting behavior of a type-II equal size Lennard-Jones mixture.
- To compare the predictive capabilities of Density Gradient Theory (DGT) with molecular dynamics simulations.
- To characterize the phase and interface behavior under varying thermodynamic conditions.
Main Methods:
- Employing Density Gradient Theory (DGT) coupled with a Lennard-Jones equation for bulk phases.
- Conducting molecular dynamics (MD) simulations for a type-II Lennard-Jones mixture.
- Defining molecular parameters from the global phase diagram of Lennard-Jones mixtures.
- Analyzing interfacial concentration profiles and interfacial tensions.
Main Results:
- Excellent agreement was found between DGT predictions and MD simulation results.
- A stable three-phase equilibrium (L1, L2, G) was consistently observed.
- The L2 liquid phase was found to completely wet the gas-liquid (GL1) interface.
- Interfacial tensions confirmed the observed wetting behavior.
Conclusions:
- Type-II Lennard-Jones mixtures exhibit permanent perfect wetting.
- No wetting transitions were observed within the explored thermodynamic ranges.
- DGT provides a reliable theoretical framework for predicting wetting phenomena in such mixtures.
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