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O: Fachverband Oberflächenphysik
O 102: Focus Session: Wetting on Adaptive Substrates III (joint session CPP/DY/O)
O 102.9: Talk
Friday, March 22, 2024, 12:15–12:30, H 0110
Chemically Active Wetting — •Susanne Liese1, Xueping Zhao2, Christoph Weber1, and Frank Jülicher3 — 1Faculty of Mathematics, Natural Sciences, and Materials Engineering: Institute of Physics, University of Augsburg, Augsburg, Germany — 2Department of Mathematical Sciences, University of Nottingham Ningbo China — 3Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
Wetting of liquid droplets on passive surfaces is ubiquitous in our daily lives, and the governing physical laws are well-understood. When surfaces become active, however, the governing laws of wetting remain elusive. Here we derive the non-equilibrium thermodynamic theory for active wetting, where the surface is active due to a binding process that is maintained away from equilibrium. We show that active binding fundamentally changes the wetting behavior, leading to steady, non-equilibrium states with droplet shapes reminiscent of a pancake or a mushroom. The origin of such anomalous shapes can be explained by mapping to electrostatics, where pairs of binding sinks and sources correspond to electrostatic dipoles along the triple line. This is an example of a more general analogy, where localized chemical activity gives rise to a multipole field of the chemical potential. The underlying physics is relevant for cells, where droplet-forming proteins can bind to membranes accompanied by the turnover of biological fuels.
Keywords: wetting; active surface; non-equilibrium thermodynamics