An adhesion model for contact electrification

Abstract

Contact electrification (CE) is a universal phenomenon that occurs at the contact interface where tribo-charges transfer from one surface to another. These CE-driven charges accumulate at the interface and can significantly affect the soft adhesive contact. So far, only a few analytical and numerical models have been proposed to partially solve the CE-induced electroadhesive contact problem. In this study, we have developed a full self-consistent contact model to study the CE-induced electroadhesion between a dielectric elastic axisymmetric parabolic surface and a dielectric rigid flat. Both surfaces are initially neutralized and undergo only one loading–unloading cycle. The surface interaction is determined by both the Lennard-Jones and the electrostatic interaction laws. The electrostatic problem is numerically solved to accurately calculate the electrostatic traction due to both the tribo-charges and bound charges. The normal traction, interfacial gap, and hysteresis loop of the force curve are thoroughly investigated. The effect of non-uniform tribo-charge density on the force curve and electrostatic traction is explored. The numerical model developed in the present work can serve as the foundation for more complex electroadhesive contact models. It also sheds light on the interfacial design of CE-related devices, e.g., contact-separation triboelectric nanogenerator.