Triboelectric\nNanogenerator-Based Near-Field Electrospinning\nSystem for Optimizing PVDF Fibers with High Piezoelectric Performance

Abstract

Electrospinning\nis an effective method to prepare polyvinylidene\nfluoride (PVDF) piezoelectric fibers with a high-percentage β\nphase. However, as an energy conversion material for micro- and nanoscale\ndiameters, PVDF fibers have not been widely used due to their disordered\narrangement prepared by traditional electrospinning. Here, we designed\na near-field electro-spinning (NFES) system driven by a triboelectric\nnanogenerator (TENG) to prepare PVDF fibers. The effects of five important\nparameters (PVDF concentration, needle inner diameter, TENG pulse\nDC voltage (TPD-voltage), flow rate, and drum speed) on the β\nphase fraction of PVDF fiber were optimized one by one. The results\nshowed that the electrospun PVDF fibers had uniform diameter and controllable\nparallel arrangement. The β phase content of the optimized PVDF\nfiber reached 91.87 ± 0.61%. For the bending test of a single\nPVDF fiber piezoelectric device, when the strain is 0.098%, the electric\nenergy of the single PVDF fiber device of NFES reaches 7.74 pJ and\nthe energy conversion efficiency reaches 13.5%, which is comparable\nto the fibers prepared by the commercial power-driven NFES system.\nIn 0.5 Hz, the best matching load resistance of a PVDF single fiber\ndevice is 10.6 MΩ, the voltage is 6.1 mV, and the maximum power\nis 3.52 pW. Considering that TENG can harvest micromechanical energy\nin the low frequency environment, the application scenario of the\nNFES system can be extended to the wild or remote mountainous areas\nwithout traditional high-voltage power supply. Therefore, the electrospun\nPVDF fibers in this system will have potential applications in high-precision\n3D fabrication, self-powered sensors, and flexible wearable electronic\nproducts.