Improving piezoelectric and pyroelectric properties of electrospun PVDF nanofibers using nanofillers for energy harvesting application

Abstract

In this study, it was aimed to increase the piezoelectric and pyroelectric properties of electrospun polyvinylidene fluoride (PVDF) nanofibers simultaneously by using specific nanofillers. Graphene oxide (GO), graphene, and halloysite nanotubes with different concentrations (0, 0.05, 0.4, and 1.6% wt/wt) were combined with PVDF solution and were fabricated in the form of nanofibers through electrospinning. Pyroelectric properties of samples were measured by submerging sealed samples in hot water (360°K) and ice (270°K). The piezoelectric properties of the samples were evaluated through bending tests. The microstructural, mechanical, and thermal properties of the electrospun PVDF nanocomposite were investigated using scanning electron microscope, Instron instrument, and thermogravimetric analysis, respectively. To further support the experimental observations for generating electric voltage in the bended nanogenerator, the PVDF nanogenerator (PNG) was also modeled by a finite element analysis based on the theory of linear piezoelectricity using COMSOL Multiphysics simulation software. Experimental results showed that adding nanofillers could improve the piezoelectric and pyroelectric properties of all samples, associated with the increment of β-phase in the nanofibers. It was concluded that adding nanofillers could increase pyroelectricity about 50% more than piezoelectricity in pristine PVDF nanofiber web. The PNG containing 1.6 wt% GO showed the highest efficiency in terms of piezoelectricity and pyroelectricity. In addition, the results showed that the ratio of piezoelectric to pyroelectric coefficients was constant (~1.5) and it was independent of the nanofiller type and content. The effect of external force and vibration frequency on the output voltage was also investigated. Increasing the compressive force and vibration frequency caused a greater output voltage. Finally, the fabricated nanogenerator was integrated on insole and elbow to investigate its energy harvesting capabilities from body movement.

A Review of Piezoelectric PVDF Film by Electrospinning and Its Applications

“…From the schematic illustration, we can see that with the addition of BT to PVDF, stronger O-HF-C hydrogen atoms will form. It is believed to form due to the high polarity of hydroxyl groups, and as a result, oriented -CH 2 /-CF 2 dipoles favor orienting along with the F atoms closer to the BT nanoparticles, which is characteristic of the β-phase [ 108 ].…”

“…Several research groups have been extensively investigating the effect of the addition of Gr in different forms on the mechanical, morphological, and electrical characteristics of electrospun PVDF nanofibers. In theory, pi bonds in Gr interact with fluorine atoms in PVDF, improving the formation of the β-phase [ 108 ].…”

“…The study by Abbasipour et al examined the effect of nanofillers such as Gr, GO, and halloysite nanotubes (HNT) on piezoelectric and pyroelectric properties of PVDF nanofibers [ 108 ]. They prepared a PVDF membrane by the conventional electrospinning technique by adding 0.05, 0.4, and 1.6 wt.% of nanofillers, and prepared sandwich structured NG using Al foils and polycarbonate sheets.…”

Solution Blow Spinning of Polyvinylidene Fluoride Based Fibers for Energy Harvesting Applications: A Review

“…The carbon atoms in graphene have a zig-zag structure which matches the zig-zag structure of the β-phase and therefore can be a strong nucleating agent [60]. Graphene oxide (GO) was more effective in enhancing piezoelectric and pyroelectric properties of PVDF than graphene [61]. Achaby et al [37] found that the α-peaks completely disappeared at the incorporation of 0.075 wt% GO and a solely β-phase was observed.…”

Improvement in energy conversion of electrostrictive composite materials by new approach via piezoelectric effect: Modeling and experiments

“…In the past few years, the requirement of wearable electronics and wireless technologies is at the source of intensive study on electrical energy harvesting from the ambient environment. [1][2][3][4][5][6][7] This great advance in research has been brought on by new developments in low-power electronics and cordless detectors such as microelectromechanical systems (MEMS) devices. [8][9][10] There is no doubt that energy harvesting is an attractive approach for wide various self-powered microsystems.…”