Hand‐powered and programmable electrowetting‐on‐dielectric droplet actuation enabled by triboelectric nanogenerator and mechanically encoded punch‐card switch array

Abstract

Electrowetting‐on‐dielectric (EWOD) enables electrical modulation of liquid contact angle and is widely used for droplet actuation; however, its reliance on bulky high‐voltage power supplies limits portability. Triboelectric nanogenerators (TENGs) provide a lightweight, mechanically driven alternative, yet existing EWOD–TENG systems still rely on electronic controllers or rapid manual actions. Here, we present a hand‐powered and mechanically programmable EWOD platform that integrates a contact‐separation TENG (CS‐TENG) with a mechanically encoded punch‐card switch array, both driven by a single hand‐crank mechanism. Hand cranking simultaneously generates high voltage for EWOD actuation and advances a punch‐card tape to sequentially trigger electrode switching according to predefined punch‐hole patterns. Unlike conventional voltage sources, the CS‐TENG delivers a constant‐charge output per cycle, leading to distinct EWOD behavior. An EWOD–TENG model with trapped charge elucidates key phenomena, including bias‐dependent asymmetric EWOD arising from dielectric charge trapping and stepwise voltage attenuation caused by capacitive EWOD loading during sequential switching. The punch‐card switch array converts physical hole patterns into time‐synchronized electrode activation, enabling programmable droplet manipulation without electronic controllers. The resulting platform executes predefined droplet operations using only a hand crank as the sole energy and control input, achieving autonomous, portable, and robust droplet control for field‐deployable microfluidic systems.