Confinement Effects in Droplet Formation on a Solid Particle.

Area of Science:

• Physical Chemistry
• Thermodynamics
• Statistical Mechanics

Background:

• Droplet formation around solid particles is crucial in phase transitions.
• Understanding equilibrium solutions is key to characterizing nucleation and growth processes.
• Comparing closed (canonical ensemble) and open (grand canonical ensemble) systems provides insights into confinement effects.

Purpose of the Study:

• To investigate the number and stability of equilibrium droplet solutions around a spherical particle in supersaturated vapor.
• To compare the behavior in a closed system (canonical ensemble) versus an open system (grand canonical ensemble).
• To explore the influence of confinement on droplet formation.

Main Methods:

• Macroscopic thermodynamic analysis.
• Classical density functional theory (DFT) with square-gradient approximation and Carnahan-Starling equation of state for a completely wettable particle.
• Classical DFT with random-phase approximation and fundamental measure theory for a poorly wettable particle.

Main Results:

• In the canonical ensemble, systems can exhibit one or three equilibrium solutions, with the third solution arising from confinement.
• The analysis revealed distinct behaviors for completely wettable versus poorly wettable particles.
• For poorly wettable particles with a small number of molecules, a solution breaking spherical symmetry was observed.

Conclusions:

• Confinement significantly influences the number and stability of equilibrium droplet solutions.
• DFT provides a powerful tool to study droplet formation at a molecular level, capturing complex phenomena like symmetry breaking.
• The findings contribute to a deeper understanding of nucleation and phase transitions in confined environments.