Pattern formation in binary fluid mixtures induced by short-range competing interactions.

Area of Science:

• Computational chemistry and soft matter physics.

Background:

• Simple mixtures of molecules can exhibit complex structural organization.
• Depletion forces play a significant role in driving microheterogeneity in non-ideal mixtures.

Purpose of the Study:

• To investigate pattern formation in a model system of diatomic molecules and monomers.
• To characterize effective inter-site potentials from simulation data.
• To explore the impact of charge incorporation on system structure.

Main Methods:

• Utilizing molecular dynamics simulations and integral equation calculations.
• Employing inverse Monte Carlo and integral equation inversion for potential extraction.
• Analyzing pair correlation functions to understand structural properties.

Main Results:

• Observed pattern formation (microheterogeneity) driven primarily by depletion forces.
• Extracted effective potentials show characteristic short-range attraction and long-range repulsion.
• Incorporating charges into the model, representing room temperature ionic liquids, led to more pronounced and stable intermediate-range order.

Conclusions:

• Depletion forces are key drivers of microheterogeneity in simple mixtures.
• Effective potentials derived from simulations accurately reflect interaction characteristics.
• Charge interactions significantly influence the development of order in coarse-grained ionic liquid models.