Poly(vinylidene fluoride-trifluoroethylene) Nanowires with Highly Anisotropic Piezoelectric Response Fabricated from Melt Phase

We fabricated highly ordered poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) nanowires with anisotropic piezoelectric response by using a template-free solution method. The molecular dipoles in the nanowires were preferentially oriented parallel relative to the substrate plane, while the macromolecular backbones were oriented perpendicular to the substrate plane. As the piezoelectric effect in the organic ferroelectric polymer originates from the alignment of molecular dipoles, this distinct molecular orientation gives rise to a significant difference in lateral and vertical piezoelectric responses in the nanowires. A flat-on lamellar structure and a thin layer melt crystallization nanowire formation mechanism were proposed. The results demonstrate a facile and efficient route for fabricating P(VDF-TrFE) nanowires with highly anisotropic piezoelectric response that are promising for nanoscale energy harvesting devices.