Guiding Falling Droplets with Corona Electric Field: Dynamics, Trajectory Control, and Applications in Printing and Rain Shelter

Droplet manipulation under electric fields is important for applications in microfluidic systems, precision printing and surface protection. The deflection behavior of freely falling droplets in a corona induced electric field is systematically investigated. The influence of electric field intensity and initial droplet velocity on trajectory control is examined experimentally. Our results demonstrate that corona discharge enables precise control over the deflection and landing position of falling droplets. A theoretical model is established to predict the droplet landing position. Based on this control mechanism, two practical applications are demonstrated: two-dimensional precision droplet printing and active rain shelter. This work provides a systematic insight into the aerial manipulation of droplets via electric fields and offers a feasible strategy for targeted droplet deposition and surface protection.