Enhanced piezoelectric nanogenerator made of electrospun PVDF and P(VDF-TrFE) nanowebs with the addition of TrFE comonomers

Poly(vinylidene fluoride) (PVDF), a representative piezoelectric and ferroelectric polymer has been widely used as a nanogenerator for piezoelectric energy harvesting and as a sensor. Although the α-phase is generally dominant in PVDF, it has poor piezoelectric property. To improve the piezoelectric performance of PVDF, the α-phase was converted into the β-phase through stretching using electrospinning. In addition, it exhibited higher piezoelectric performance when a comonomer is added to PVDF, like a PVDF-based copolymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)). Accordingly, the effect of the comonomer TrFE on the β-phase conformation and piezoelectric performance was investigated in a nanogenerator that prepared a nanoweb with similar fiber diameters by electrospinning PVDF and P(VDF-TrFE). The microstructure of the nanoweb was investigated using scanning electron microscopy (SEM), and the crystal phase change was confirmed using an X-ray diffraction (XRD) and Fourier transform-infrared spectroscopy (FT-IR). It was confirmed that the presence of TrFE changed the interaction between atoms and formed a significant amount of β-phase, reaching the maximum β-phase at P(VDF-TrFE) 70/30. Piezoelectric tests showed excellent electrical characteristics of 8 V and 2.29 µW.