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Diffusiophoresis of two-dimensional liquid droplets in a phase-separating system
N Vladimirova1, A Malagoli, R Mauri
1Department of Chemical Engineering, The City College of CUNY, New York, New York 10031, USA.
Summary
Simulations show phase-separating liquid drops move due to capillary forces. Drop behavior, including speed, growth, and interaction, depends on concentration differences and capillary number, aligning with experiments.
Area of Science:
- Fluid dynamics
- Phase separation dynamics
- Computational physics
Background:
- Phase-separating liquid systems exhibit complex dynamics driven by free energy minimization.
- Understanding drop motion is crucial for applications in materials science and microfluidics.
- Model H describes coupled convection and diffusion in demixing systems.
Purpose of the Study:
- To simulate and analyze the motion of phase-separating liquid drops in two dimensions.
- To investigate the influence of capillary number and concentration gradients on drop behavior.
- To explore the interactions and coalescence of multiple drops.
Main Methods:
- Numerical simulations using Model H.
- Analysis of drop speed, growth rate, and mean square displacement.
- Investigation of capillary forces and their effect on drop interactions.
Main Results:
- Single drop speed is proportional to concentration gradient and inversely proportional to capillary number.
- Drops shrink or grow/move randomly based on initial concentration difference.
- Two drops exhibit mutual attraction, leading to coalescence or repulsion based on concentration.
- Drop growth rate and movement align with experimental data.
Conclusions:
- Capillary forces are the primary drivers of phase-separating drop motion.
- Concentration gradients and capillary number dictate drop dynamics and interactions.
- Simulations provide a framework for predicting drop behavior in various scenarios.
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