Electrostatically responsive liquid gating system for controlled microbubble generation†

Microbubbles have attracted considerable attention due to their distinctive properties, such as large surface area, inherent self-compression, and exceptional mass transfer efficiency. These features render microbubbles valuable across a diverse range of industries, such as water treatment, mineral flotation, and the food industry. While several methods for microbubble generation exist, the gas–liquid membrane dispersion technique emerges as a reproducible and efficient alternative. Nevertheless, conventional approaches struggle to achieve active in situ control of bubble generation. In this study, we introduce an electrostatically responsive liquid gating system (ERLGS) designed for the active management of microbubble production. Utilizing electric fields and anionic surfactants, our system showcases the capability to dynamically regulate bubble size by manipulating the solid–liquid adsorption. Experiments confirm that this active control relies on the electrostatic adsorption and desorption of anionic surfactants, thereby regulating the interactions among the solid–liquid–gas interfaces. Our research elucidates the ERLGS's ability of precisely controlling the generation of bubbles in situ, enabling nearly one-order-of-magnitude change in bubble size, underscoring its applicability in various fields.

Keywords: Liquid gating system; Electrostatic response; Anionic surfactants; Adsorption and desorption; Microbubbles.