Measuring gas discharge in contact electrification

Abstract Contact electrification in a gas medium is usually followed by partial surface charge dissipation caused by gas breakdown triggered during separation. It is widely assumed that such discharge obeys the classical Paschen’s law, which describes the general dependence of breakdown voltage on the product of gas pressure and gap distance. However, quantification of this relationship in contact electrification involving insulators is impeded by challenges in nondestructive in situ measurement of the gap voltage. The present work proposes and implements an electrode-free strategy for capturing discrete discharge events by monitoring the gap voltage via Coulomb force, providing experimental evidence for a Paschen-type behavior for nitrogen breakdown between a silicone-acrylic contact pair. The method offers an alternative approach for characterizing either the ionization energies of gases or the secondary-electron-emission properties of surfaces without the requirement of an external voltage source, which can potentially benefit applications ranging from the design of insulative materials to the development of triboelectric sensors and generators.