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The application of physical fields is crucial for droplet generation and manipulation, underpinning technologies like printing, microfluidic biochips, drug delivery, and flexible sensors. Despite advancements, precise micro/nanoscale droplet generation and accurate microfluidic reactions remain challenging. Inspired by the liquid ejection mechanisms in microscopic organisms, an electrostatic manipulator for the precise capture, emission, and transport of microdroplets is proposed. This approach enables the controlled and periodic emission of nanoscale daughter droplets from microscale parent droplets, achieved through dielectric pinning on surfaces and electrostatic field-driven forces. Results show precise nanoscale droplet release on inert polymer surfaces, enabling directional, contamination-free liquid manipulation. Moreover, leveraging surface treatment techniques and robust electrostatic force-driven transportation, a versatile strategy for droplet generation and manipulation, spanning from microfluidic devices to chemical reaction operations. The novel droplet manipulation phenomena and control strategies can advance the fields of electrostatic-based microfluidics, materials fabrication, and beyond.
Li et al. (Mon,) studied this question.