Self-Propelled Motion of a Droplet Induced by Marangoni-driven Spreading

TL;DR

This paper demonstrates the self-propelled motion of aniline oil droplets on water driven by Marangoni effects, showing different motion modes influenced by droplet size and concentration, supported by experimental and simulation results.

Contribution

It introduces a new experimental observation of droplet self-propulsion driven by Marangoni spreading and provides a simulation model to reproduce the motion modes.

Findings

Droplets exhibit circular or beeline motion depending on initial conditions.

Velocity decreases with increasing droplet volume and solution concentration.

Simulation successfully reproduces observed motion modes.

Abstract

We report the generation of directed self-propelled motion of a droplet of aniline oil with a velocity on the order of centimeters per second on an aqueous phase. It is found that, depending on the initial conditions, the droplet shows either circular or beeline motion in a circular Petri dish. The motion of a droplet depends on volume of the droplet and concentration of solution. The velocity decreases when volume of the droplet and concentration of solution increase. Such unique motion is discussed in terms of Marangoni-driven spreading under chemical nonequilibrium. The simulation reproduces the mode of motion in a circular Petri dish.