Work

Chemomechanical motility modes of partially wetting liquid droplets

Year: 2025

Type: article

Abstract: We consider a simple thermodynamically consistent model that captures the self-organized chemomechanical coupling resulting from the interplay between autocatalytically reacting surfactants, the Marangoni effect, and wetting dynamics. An ambient bath of surfactant acts as a chemostat and provides the system with chemical fuel, thereby driving it away from thermodynamic equilibrium. We find that a positive feedback loop between the local reactions and the Marangoni effect induces surface tension gradients that allow for self-propelled droplets. Besides simple directional motion, we find crawling and shuttling droplets as well as droplets performing random walks, thus exploring the entire substrate. We study the occurring chemomechanical motility modes and show how the observed dynamic states emerge from local and global bifurcations. Due to the underlying generic thermodynamic structure, we expect that our results are relevant not only to directly related biomimetic droplet systems but also to structurally similar systems like chemically active phase-separating mixtures.

Source: Physical Review Fluids

DOI: 10.1103/f3ck-dx5c

Authors: Florian Voss, Uwe Thiele

Institution: University of Münster

Language: English

Topic: Micro and Nano Robotics

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: National Science Foundation, Deutsche Gesellschaft für Parkinson und Bewegungsstörungen, Deutsche Forschungsgemeinschaft, Kavli Institute for Theoretical Physics, University of California, Santa Barbara

Awards: G3608589354, G4955048828, Kavli Institute for Theoretical Physics