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Piezoelectricity of Well-Aligned Electrospun Fiber Composites

This investigation aims to study energy conversion and actuation properties of the modified near-field electrospinning piezoelectric polyvinylidene fluoride (PVDF) fibers. Conceptually, the mixed PVDF solution was electrospun, and highly aligned fibers were collected using a rotating glass tube collector. In order to grow β-form extended-chain crystallites in PVDF fibers, during electrospining process, a polymer solution experiences two forces. For the purpose of producing a stable jet of polymer solution, under a high electric field (1.6×107 V/m), polymer jet was elongated and accelerated due to a greater Coulombic force. The other one is a strong extensional force when a glass tube collector (rotating speed: 700-2100 r.p.m) was used to collect PVDF fibers. After carbon nanotubes (CNTs) were added to the orderly aligned PVDF fibers (diameter: 0.2-1.6 μm), CNTs may interact with PVDF, resulting in obvious β-phase enhancement. Software of FEA with model solution was employed to assist us in estimating the two significant piezoelectric actuation deformations. In actuation experiment, the suspended PVDF fiber presented a large deflection under high electric field. The bending results in a mechanical strain (0.05%-0.1%) distributed along the PVDF fibers, and the induced maximum voltage and current output of the harvesters were 43.6 mVp-p and 240 nIp-p at 15-Hz impact frequency, respectively.