Lotus leaf-inspired superhydrophobic piezoelectric nanofiber films for moisture-proof pressure sensing and energy harvesting

High-performance and moisture-proof piezoelectric nanogenerators (PENGs) are in high demand for pressure sensing and energy harvesting. Inspired by super-hydrophobic structure of lotus leaf, we propose a moisture-proof nanofiber film-based PENG by designing the well-defined microspheres on the surfaces of electrospinning PVDF/ZnO nanorods (NRs) nanofibers, which can long-term serve even under high humidity. More interestingly, attributed to the synergistic effect of the electric field induced crystal transformation of PVDF, stress concentration effect resulting from microspheres and ZnO-NRs, as well as enhanced piezoelectric effect of ZnO-NRs, the as-prepared PENG exhibits various merits, including ultra-high piezoelectric output (103.1 V) with power density of -2.36 mu W cm(-2), fast response time (30.8 ms) and excellent long-term stability over 10,800 cycles. Thanks for the outstanding piezoelectric properties of our PENGs, they can not only be applied in capturing energy such as wind energy, but also employed as flexible wearable sensors to monitor human motions/physiological signals and realize human-machine interaction. This work provides an unexplored strategy for multifunctional flexible piezoelectric sensor with excellent practicability and moisture-proof characteristic.