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O: Fachverband Oberflächenphysik
O 102: Focus Session: Wetting on Adaptive Substrates III (joint session CPP/DY/O)
O 102.3: Talk
Friday, March 22, 2024, 10:15–10:30, H 0110
High Voltages Generated by Moving Water Drops — •Stefan Weber1,2, Pravash Bista2, Aaron Ratschow3, and Hans-Jürgen Butt2 — 1Institute for Photovoltaics, University of Stuttgart — 2MPI for Polymer Research, Mainz — 3Institute for Nano- and Microfluidics, TU Darmstadt
Water drops on insulating, hydrophobic substrates can generate electric potentials of kilovolts upon sliding for a few centimeters. We show that the drop saturation voltage corresponds to an amplified value of the solid-liquid surface potential at the substrate. The amplification is given by the substrate geometry, the drop and substrate dielectric properties and the Debye length within the liquid. Next to enabling an easy and low-cost way to measure surface- and Zeta potentials, the high drop voltages have implications for energy harvesting, droplet microfluidics and electrostatic discharge protection.
Keywords: Dynamic Wetting; Droplets; Triboelectricity; Zeta potential