Layered interfaces between immiscible liquids studied by density-functional theory and molecular-dynamics simulations

Area of Science:

• Physical Chemistry
• Computational Physics
• Materials Science

Background:

• Understanding the structure of interfaces between immiscible liquids is crucial for various chemical and physical processes.
• Previous studies often employed simplified models or experimental techniques with limited resolution.

Purpose of the Study:

• To investigate the structural properties at the interface of two immiscible liquids.
• To explore the influence of liquid-phase diagram parameters on interfacial structure.
• To identify the relationship between interfacial behavior and the drying transition.

Main Methods:

• Utilized density-functional theory (DFT) and molecular-dynamics (MD) calculations.
• Modeled immiscible liquids using Lennard-Jones potentials with suppressed attractive interactions between unlike particles.
• Analyzed density profiles and adsorption at the liquid-liquid interface.

Main Results:

• Observed density profile oscillations in a limited region of the liquid-phase diagram (density, temperature).
• Found that approaching liquid-vapor coexistence leads to significant depletion and vanishing of density layering.
• Adsorption analysis indicated a strong connection to the drying transition.

Conclusions:

• The structural behavior at the interface of immiscible liquids is sensitive to thermodynamic conditions.
• The vanishing of density layering and observed depletion near liquid-vapor coexistence are indicative of a drying transition.
• DFT and MD simulations provide valuable insights into complex interfacial phenomena.