The Triboelectric Properties of Ex Situ Transferred Bioinspired Polydopamine Films

Abstract Triboelectric nanogenerators (TENGs) are promising for energy harvesting, while biomimetic polydopamine films offer extraordinary mechanical resilience and adhesion. Free‐standing polydopamine films are synthesized at the air/water interface, with thicknesses from 12 to 80 nm and lateral sizes over 5 cm ² , enabling easy electrode transfer. The effect of thickness and performance is examined against four polymers: polytetrafluoroethylene, polystyrene, polymethylmethacrylate, and polydimethylsiloxane, with the highest separation force for the latest. Boric acid functioned as an (anti)oxidation agent, improving polydopamine thickness control, mechanical strength, and adhesion to PDMS, leading to a charge density of up to 1.37 nC cm ⁻² . This nanoarchitecture enabled a simple TENG with an energy density of 1964.64 ± 144.45 µJ m ⁻² and a power density of 78.51 ± 1.93 mW m ⁻² . Long‐term stability is confirmed by monitoring peak‐to‐peak current over 10 000 contact‐separation cycles, stabilizing at ≈0.8 µA. The demonstrated device could power up a microdevice and work as a self‐powered pressure sensor. This methodology can be scaled for more efficient polydopamine‐based TENGs, including multilayer or flexible nanogenerators.