Cluster formation in fluids with competing short-range and long-range interactions.

Area of Science:

• Thermodynamics
• Fluid Dynamics
• Materials Science

Background:

• Investigating fluid behavior at low densities is crucial for understanding phase transitions.
• The solute-attraction-long-ranged-repulsion (SALR) potential models effective interactions after integrating out solvent degrees of freedom.
• Understanding cluster formation mechanisms, such as micelle formation, is key in soft matter physics.

Purpose of the Study:

• To develop a molecular thermodynamic model for fluids with SALR potentials.
• To analyze the low-density behavior and cluster formation in these systems.
• To explore novel phase behaviors and nucleation pathways.

Main Methods:

• Development of a molecular thermodynamic model.
• Analysis of fluid behavior under SALR potentials.
• Large-scale Monte Carlo simulations.

Main Results:

• Cluster formation observed when attractive and repulsive forces nearly balance.
• Discovery of a novel coexistence between low-density and high-density cluster phases.
• Development of a formula for average cluster size.
• Thermodynamic stability of the cluster fluid phase confirmed by simulations.

Conclusions:

• The SALR potential leads to significant cluster formation and unique phase behaviors.
• A new pathway for non-classical crystal nucleation, involving precursor droplets, is proposed.
• The findings have implications for understanding phase transitions and nucleation in various fluid systems.