Controllable High‐Speed Electrostatic Manipulation of Water Droplets on a Superhydrophobic Surface

다국어 초록 (Multilingual Abstract)

Biological processes and technological applications cannot work without liquid control, where versatile water droplet manipulation is a significant issue. Droplet motion is conventionally manipulated by functionalizing the target surface or by utilizing additives in the droplet, still, with uncontrolled limitation on superhydrophobic surfaces since droplets are either unable to move fast or are difficult to stop while moving. A controllable high‐speed “all‐in‐one” no‐loss droplet manipulation, that is, in‐plane moving and stopping/pinning in any direction on a superhydrophobic surface, with electrostatic charging is demonstrated. The experimental results reveal that the transport speed can vary from zero to several hundreds of millimeters per second. Controlled dynamic switching between the onset moving state and the offset pinning state of a water droplet can be achieved by out‐of‐plane electrostatic charging. This work opens the possibility of droplet control techniques in various applications, such as combinatory chemistry, biochemical, and medical detection.
A revolution to the microfluidic device commonly used in biological processes and technological applications is demonstrated. The new approach, which moves drops at a high speed with low adhesion or retention by electrostatic attraction or repulsion on a superhydrophobic surface, can enable microfluidic experiments to be conducted more efficiently, cost‐effectively, and at larger scales.