biostudies-literatureBista PDeutsche ForschungsgemeinschaftEuropean Research Council5045-5052https://www.ebi.ac.uk/biostudies/studies/S-EPMC11220910biostudies-literatureUnknown20(26)Spontaneous charge separation in drops sliding over a hydrophobized insulator surface is a well-known phenomenon and lots of efforts have been made to utilize this effect for energy harvesting. For maximizing the efficiency of such devices, a comprehensive understanding of the dewetted surface charge would be required to quantitatively predict the electric current signals, in particular for drop sequences. Here, we use a method based on mirror charge detection to locally measure the surface charge density after drops move over a hydrophobic surface. For this purpose, we position a metal electrode beneath the hydrophobic substrate to measure the capacitive current induced by the moving drop. Furthermore, we investigate drop-induced charging on different dielectric surfaces together with theSoft matterSurface charge density and induced currents by self-charging sliding drops.PMC11220910ERC advanced grant DYNAMO (agreement no. 883631)Collaborative Research Centre (SFB) 1194883631Focus Programme (SPP) 2171Stetten AZButt HJWeber SALRatschow ADBista PfalseSurface charge density and induced currents by self-charging sliding drops.Spontaneous charge separation in drops sliding over a hydrophobized insulator surface is a well-known phenomenon and lots of efforts have been made to utilize this effect for energy harvesting. For maximizing the efficiency of such devices, a comprehensive understanding of the dewetted surface charge would be required to quantitatively predict the electric current signals, in particular for drop sequences. Here, we use a method based on mirror charge detection to locally measure the surface charge density after drops move over a hydrophobic surface. For this purpose, we position a metal electrode beneath the hydrophobic substrate to measure the capacitive current induced by the moving drop. Furthermore, we investigate drop-induced charging on different dielectric surfaces together with the2024-01-01T00:00:00Z2024 Jul2025-04-06T00:13:18.144Z2025-04-06T00:13:18.144ZS-EPMC112209103863908610.1039/d4sm00205a