An Oscillation System Based on a Liquid Metal Droplet and Pillars under a Direct Current Electric Field

Gallium-based liquid metal is a new class of material that has attracted extensive attention due to its excellent deformation characteristics and great potential in applications. Based on the deformation characteristics of liquid metal droplets, researchers have developed many oscillation systems composed of gallium indium tin alloy (GaInSn) droplet and graphite, or aluminum-doped gallium indium alloy (Al-GaIn_24.5) droplet and iron, and so on. Rather than the oxidation and deoxidation mechanisms used in previous systems, an oscillation system that can achieve gallium indium alloy (EGaIn) droplet oscillation with the frequency of 0–29 Hz is designed depending on the interactions between the electric field, pillars, sodium hydroxide, and the droplet. The forces on the droplet are analyzed specifically, which have a great influence on droplet deformation. Additionally, the effects of factors such as voltage, the concentration of sodium hydroxide (NaOH) solution, and droplet size on the droplet oscillation are elucidated based on the force analysis, enabling the flexible control of the oscillation frequency and amplitude of the droplet. This work provides a new perspective on the design of oscillation systems and further enhances our understanding of the deformation of gallium-based liquid metal droplets.