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.

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2026 The Author(s). Droplet published by Jilin University and John Wiley & Sons Australia, Ltd.