Self-Poled Sausage-Like PVDF Nanowires Produced by Confined Phase Inversion as Novel Piezoelectric Nanogenerators

Piezoelectric poly(vinylidene fluoride) (PVDF) nanowires are of particular interest for energy harvesting as they are ultra-sensitive to small vibrations. Here, a new, cost-effective, and scalable approach to producing PVDF nanowires with strongly enhanced power output is presented. The method combines template-wetting in cylindrical nano-confinement with anisotropic solvent-nonsolvent phase inversion to yield a fully novel nanowire morphology consisting of “sausage-like” strings of nano-domains. Dynamic numerical simulations of the phase inversion reveal the formation of these structures to be subject to a very rich and complex phenomenology. The simulated dependence of the feature size on the degree of confinement agrees with the experimentally observed trend. It is unambiguously demonstrated that the sausage-like nano-generators upsurge the power density to 280% compared to normal nanowires. Finite element modeling explains how the higher deformability of the sausage-like nanostructures gives rise to this significant enhancement in piezoelectric performance.