Design of a simple unfailing microdroplet dispenser using a droplet pusher based on a superhydrophobic surface

Microdroplet injection technology is crucial in various fields; however, the accurate and efficient control of microliter-sized drops remains an active research area. Existing technologies often rely on expensive equipment or complex control systems. In this study, we propose a novel, simple, and cost-effective approach for the precise separation of microliter-sized drops. This study employed an aluminum plate with a perforated surface that was treated as superhydrophobic. This surface prevented droplets from wetting the aluminum surface, thereby ensuring perfect separation from the nozzle. We conducted experiments to separate drops of various volumes by adjusting the hole diameter in the aluminum plate. A quantitative analysis was performed to explore the correlation between the critical minimum droplet size and the hole diameter. This method is expected to significantly broaden the applicability of drop separation technology across different industrial sectors owing to its straightforward design, low manufacturing costs, and excellent reusability.