Highly aligned P(VDF-TrFE) nanofibers with anisotropic piezoelectricity fabricated by electrospinning for physical sensing devices

This manuscript describes an electrospinning method for fabrication of highly aligned poly(vinylidene fluoride-trifluoroethylene) copolymer (P(VDF-TrFE)) nanofibers. In our experiments, micro-patterned parallel electrodes are used to modify the electric field nearby the collector, and electrospun nanofibers achieve good alignment when the gap distance of the parallel electrodes is larger than 200 μm with a nozzle-collector distance of 70 mm. The aligned nanofibers show excellent piezoelectricity after annealing at 120□ at 120 for 2 hours. It is found that the output of highly aligned P(VDF-TrFE) fibers is greatly improved, compared to that of randomly oriented fibers. The P(VDF-TrFE) fibers demonstrate anisotropic piezoelectricity, which means higher charge output with a strain in the axial direction of the nanofibers than that under a strain in other directions. In addition, the alignment of the P(VDF-TrFE) nanofibers leads to the anisotropic hydrophobicity.