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Energetics-based model for a diffusiophoretic motion of a deformable droplet.
Hiroyuki Kitahata1, Yuki Koyano2, Yasuaki Kobayashi3,4
1Chiba University, Department of Physics, Graduate School of Science, Chiba 263-8522, Japan.
Physical Review. E
|April 18, 2026
Summary
This study models deformable droplets undergoing diffusiophoretic motion. Three stable states were identified: immobile circular, immobile elliptical, and mobile elliptical, with transitions between them discussed.
Area of Science:
- Physical Chemistry
- Fluid Dynamics
- Soft Matter Physics
Background:
- Diffusiophoresis drives particle motion via chemical gradients.
- Droplet deformation influences its transport dynamics.
- Surface tension gradients are key in interfacial phenomena.
Purpose of the Study:
- To develop a mathematical model for the diffusiophoretic motion of a deformable droplet at a liquid surface.
- To investigate the role of droplet deformation in diffusiophoretic transport.
- To identify and analyze the stable states of the droplet system.
Main Methods:
- Constructed a free energy functional including surface and line energies.
- Derived time-evolution equations for translational and elliptical deformation.
- Analyzed droplet behavior by considering second-mode deformation.
Main Results:
- Identified three distinct stable states for the droplet: immobile circular, immobile elliptical, and mobile elliptical.
- The mobile state features elliptical deformation with the minor axis aligned with the motion direction.
- Characterized the transitions between these stable states.
Conclusions:
- The mathematical model successfully captures the diffusiophoretic motion of deformable droplets.
- Droplet deformation significantly impacts its stable states and motility.
- Understanding these states is crucial for controlling droplet behavior in microfluidic and interfacial systems.
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