A facile approach to characterize gas slug inside a microfluidic channel employing discrete solid-liquid contact electrification

In this study, we first suggested a simple technique for characterizing gas slugs in gas-liquid two-phase microfluidic system. By using electric potential that is spontaneously generated by solid-liquid contact electrification, the properties of gas slugs, including flow rate, are precisely investigated. According to the experimental investigations on parameters that affect electric potential, gas slugs have been verified to behave similarly to a point charge. Given that the electric charge is always spontaneously generated in all cases of solid-water contact, this pioneering technique, which is the first to apply this concept to characterization, will significantly broaden the applicability of the contact electrification phenomenon.