Spontaneous motion of a droplet coupled with a chemical wave

TL;DR

This paper introduces a new model explaining how chemical reaction patterns inside a droplet can induce spontaneous motion through surface tension changes, supported by numerical and experimental evidence.

Contribution

It presents a novel framework linking internal chemical waves to droplet motion via Marangoni effects, validated by simulations and experiments.

Findings

Chemical waves induce surface tension gradients

Droplet motion correlates with internal pattern dynamics

Numerical results match experimental observations

Abstract

We propose a novel framework for the spontaneous motion of a droplet coupled with internal dynamic patterns generated in a reaction-diffusion system. The spatio-temporal order of the chemical reaction gives rise to inhomogeneous surface tension and results in self-propulsion driven by the surrounding flow due to the Marangoni effect. Numerical calculations of internal patterns together with theoretical results of the flow fields at low Reynolds number well reproduces the experimental results obtained using a droplet of Belousov-Zhabotinsky (BZ) reaction medium.