Charge accumulation kinetics at a liquid–solid interface depend on liquid chemistry

Abstract

Contact electrification and charge transfer even exist at a liquid–solid interface when continuous droplets move on the dielectric surface. However, the charge accumulation kinetics on the solid surface remain to be studied. Here, we have investigated the development of static charges accumulated on the surface of dielectric solid materials when continuous droplets slide on the solid surface from the liquid chemistry perspective at the atomic level. Various solutions are employed in the experiments, and we have observed that in liquid–solid systems charge accumulation rates on a solid surface depend on the liquid chemistry. The chemical properties of a liquid, such as the ionic diameters of the cations, concentration and pH, display stronger modulations of charge accumulation rates, than droplet movement or the physical properties of solid materials, meaning that more chemical factors need to be considered in charge transfer at a liquid–solid interface. We propose this result both from the difference in migration rate of cations to the charged solid surface and the rearrangement of the electric double layer at a liquid–solid interface under successive liquid droplets.