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Probing wetting properties with self-propelled droplets.
Last modified: 2024-11-28
Abstract
The wetting phenomenon is extensively explored in equilibrium physics, with applicationsspanning various natural and technological contexts . On the other hand, the field of active matter is a branch of physics that deals with systems composed of active particles, agentscapable of extracting energy from the environment and converting it into persistent motion in a specific direction. Although the convergence of these research areas may seem uncon-ventional, recent experimental works demonstrate the utility of this approach in elucidating the behavior of self-propelled droplets on substrates, and specify the meaning of what we called active wetting. This research aims at developing a computational model of a drop filled with self propelled agents, to bring together relevant insights towards both areas: wetting and active matter. To deal with the wetting properties, the selected model builds upon a well-establishedPotts model featuring three states: water, air, and a hydrophobic substrate [6]. Additionally, an aproach to introduce activity to the droplet are proposed: an effective stochastic field actingon the droplet’s center of mass. To validate the computational simulations against real-world experiments,we propose an experimental setup employing droplets filled with micro swimmers (Paramecium Caudatum) under varying conditions to investigate the influence of activity on the wetting behavior over a super hydrophobic surface. On the computational front, we examine how thetheoretical equilibrium wetting states of a droplet on a micro pillared super hydrophobic surface, changes across a spectrum of activity intensities. Our results show that the activity can drive the system to the dryer state, exploring the meta-stability toward the direction of the free energy minimum, which allows droplet movement with less attachment to the surface.