Stretchable Electrospun PVDF-HFP/Co-ZnO Nanofibers as Piezoelectric Nanogenerators

Abstract

Herein, we investigate the morphology, structure and piezoelectric performances of neat polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) and PVDF-HFP/Co-ZnO nanofibers, fabricated by electrospinning. An increase in the amount of crystalline β-phase of PVDF-HFP has been observed with the increase in Co-doped ZnO nanofiller concentration in the PVDF-HFP matrix. The dielectric constants of the neat PVDF-HFP and PVDF-HFP/2 wt.% Co-ZnO nanofibers are derived as 8 and 38 respectively. The flexible nanogenerator manipulated from the polymer nanocomposite (PVDF-HFP/Co-ZnO) exhibits an output voltage as high as 2.8 V compared with the neat PVDF-HFP sample (~120 mV). These results indicate that the investigated nanocomposite is appropriate for fabricating various flexible and wearable self-powered electrical devices and systems.

Figure 1

Schematics of the sample preparation and the electrospinning setup.

Figure 2

Schematic representation of (a) flexible nanogenerator and (b) piezoelectric experimental setup.

Figure 3

(a,b) SEM images (c,d) TEM images and (e,f) XRD patterns of undoped ZnO and Co-doped ZnO nanorods.

Figure 4

x-ray diffraction patterns of neat PVDF-HFP and its nanocomposites.

Figure 5

(a) FTIR spectra of neat PVDF-HFP and the nanocomposites.

Figure 6

SEM images of (a) neat PVDF-HFP, (b) PVDF-HFP/1 wt.% ZnO, (c) PVDF- HFP/0.5 wt.% Co-ZnO, (d) PVDF-HFP/1 wt.% Co-ZnO, (e) PVDF-HFP/2 wt.% Co-ZnO.

Figure 7

(a) Variation of dielectric constants (ϵ′) with frequency, (b) variation of dielectric loss (ϵ″) with frequency.

Figure 8

(a) Generation of output voltages from neat PVDF-HFP and its nanocomposites, (b) the output voltages as a function of the Co-doped ZnO filler loading.

Figure 9

The output performance of the piezoelectric nanogenerator (PVDF-HFP/2 wt% Co-doped ZnO nanofibers) as a function of different frequencies.

Figure 10

Working mechanism under pressing releasing mechanical force.