Electrospun PVDF fibers on bio-wings using multi-spinnerets

In this study, a cylindrical glass tube for near-field electrospinning (NFES) with multi-spinnerets is modified to fabricate polyvinylidene fluoride (PVDF) nanofibers on polyethylene terephthalate (PET) in large area. For the process, the traditional NFES is replaced by micro-drills technology which is used to design multi-spinnerets and drill spinnerets on the solder balls. PVDF solutions were formulated with 18 wt % and 44.2 μS/cm of the conductivity. When the electric field of 1.6 × 10⁷ V/m overcomes the surface tension, the Taylor cone can be formed. After the surface tensions of the solution are overcome, PVDF piezoelectric fibers are spun from the Taylor cone tip and collected by the cylindrical glass tube at the tangential velocity of 1779.9 mm/s. Then, after the PVDF piezoelectric fibers were heated at 65°C for 1hour, PVDF fibers with higher piezoelectric β-phase crystallization can be obtained with diameters from 2 μm to 5 μm. Finally, PVDF piezoelectric fibers are packaged on parallel electrodes. By vibrating the fibers with frequency from 2~9 Hz, a maximum peak voltage of 86.9 mV can be observed. The wing of Bear Cicada was used to test the output voltage of PVDF fibers. The as-fabricated PVDF by multi-spinnerets can be applied to power scavenger, sensing devices, actuators, and biomedical purposes in the future.