Lennard-Jones systems near solid walls: computing interfacial free energies from molecular simulation methods.

Area of Science:

• Computational physics
• Materials science
• Chemical engineering

Background:

• Understanding interfacial phenomena is crucial for predicting material behavior.
• Interfacial free energies govern wetting and adhesion properties.
• Molecular dynamics simulations offer insights into nanoscale interactions.

Purpose of the Study:

• To compute wall-liquid and wall-crystal interfacial free energies for a modified Lennard-Jones system.
• To investigate the influence of wall structure and interaction parameters on interfacial properties.
• To determine the conditions leading to partial wetting.

Main Methods:

• Utilized molecular dynamics simulations and computational techniques.
• Employed thermodynamic integration, pressure tensor anisotropy, and non-equilibrium work methods.
• Applied Cahn's adsorption equations based on Gibbs' interfacial thermodynamics.

Main Results:

• Calculated interfacial free energies for flat and structured walls under varying conditions (density, temperature, interaction strength, lattice constant).
• Determined contact angles by combining wall-liquid, wall-crystal, and crystal-liquid interfacial energies.
• Identified specific parameter ranges that result in partial wetting.

Conclusions:

• The study successfully quantifies interfacial free energies and contact angles for a model system.
• Results provide a foundation for understanding and predicting wetting phenomena in diverse applications.
• Computational methods are validated for characterizing complex interfacial thermodynamics.