Identifying the mechanism of charge dissipation processes in electrostatic induced microdischarges

Electrostatic discharges (ESD) can be induced by contact electrification between touching objects, which has been studied for many centuries; however, the fundamental mechanism of the charge transfer processes remains inexplicit or even controversial [1]. A limiting factor is that an ESD usually occurs after the object separation, which leads to significant charge dissipation and hinders a quantitative measurement of the real amount of transferred charge [2–4]. Moreover, electrostatic induced microdischarge is not as well understood as external source induced microdischarge due to dynamic separation [5]. In this work, we based on a two-dimensional fluid method, investigate the microdischarge behavior of dissimilar objects (metals or insulators) during a dynamic separation ranging from nanometers to micrometers and millimeters. Typical processes for charge dissipation, such as field emission, secondary electron emission, background charge absorption, and ionization charge absorption, are implemented and their effects are examined at different dimensional scales. The Paschen’s curve describing the breakdown voltages driven by ESD is obtained and its differences from the conventional DC breakdown are discussed. More interestingly, phenomena such as multiple discharges and charge mosaics are also observed and the physical mechanisms are further investigated. The results from this study are beneficial in precisely understanding the ESD fundamentals during the charge dissipation with coupling effects, which inform the control of the design of miniaturized electrostatic devices, such as electrostatic chuck and triboelectric nanogenerator for practical applications.