Synergistic biomimetic droplet transport platform based on Nepenthes -inspired self-propulsion and triboelectric velocity modulation

Bionic self-propelled droplet transport technology holds immense potential in microfluidic systems. However, existing passive strategies are often constrained by contact line pinning at vertical structures and insufficient durability of functional coatings, while frequently overlooking the kinetic decay induced by solid–liquid triboelectric charging. To address this, this study proposes a self-propelled droplet platform capable of velocity regulation. On one hand, femtosecond laser etching was employed to construct a dual-slope coupled, hierarchical wedge structure. This reconfigures vertical steps into smooth inclines to mitigate droplet pinning, while simultaneously providing physical anchorage points for nano-hydrophobic coatings on the etched micro/nano-textured surface. On the other hand, to counteract the electrostatic deceleration effect during long-distance transport, a back-grounded conductor structure was introduced. Leveraging electrostatic induction and shielding mechanisms, this design significantly reduced the cumulative surface potential from −198 to −98.7 V after 60 consecutive transport cycles. Furthermore, by switching the mode of the back conductor, the platform enables droplet velocity control while simultaneously outputting stable triboelectric signals. The average droplet movement speed on the platform reaches 44.77 mm s−1. This synergistic biomimetic platform unifies wear-robust, residue-free, self-propelled transport with programable triboelectric velocity gating, enabling residence-time-defined droplet microreactors/digital microfluidics, and in situ self-powered sensing.