75th Annual Meeting of the APS Division of Fluid Dynamics (November 20, 2022 — November 22, 2022)

V0044: Self-propelled volatile droplets

Authors

• Nayoung Kim, University of Twente
• Pallav Kant, University of Cambridge
• Mathieu Souzy, INRAE, Aix Marseille University
• Detlef Lohse, University of Twente
• Devaraj van der Meer, University of Twente

DOI: https://doi.org/10.1103/APS.DFD.2022.GFM.V0044

When a volatile droplet is deposited on a heated conducting substrate below the boiling temperature of the liquid, it contracts rather than spreading and moves spontaneously. Increasing substrate temperature changes the propulsion mode of the droplet from slow, uniform to fast and chaotic movements. We propose that spontaneous droplet motion results from unsteady thermo-capillary convection. Due to a larger thermal gradient along the droplet interface, the droplet is exposed to stronger contracting Marangoni flow, and spontaneous symmetric breaking of Marangoni flow induces droplet motion.