Induced Piezoelectricity in Poly(vinylidene fluoride) Hybrid as Efficient Energy Harvester

Abstract

Poly(vinylidene fluoride) (PVDF) nanohybrid with organically modified two-dimensional nanoclay, prepared through solution route, has been fabricated as the energy harvester. The nanoclay induces piezoelectric phase in PVDF arising from epitaxial crystallization over the nanoclay layers. Further enhancement of piezoelectricity has been made by stretching the film at high temperature showing~80% b-phase along with some g-phase in nanohybrid. Orientation of the nanofiller along the force field creates the nanohybrid tougher and suitable for device fabrication. Mapping of piezo-domain has been constructed through piezo force microscopy indicating 100 nm dimension of the electroactive phase in stretched nanohybrid as opposed to almost zero size in pure PVDF. Structural alteration has also been confirmed through spectro-scopic and thermal measurements. Morphology also supports the formation of b-phase in presence of nanoparticle (spherulite to needle like morphology). The piezoelectric coefficient shows a significant increase after processing due to greater piezoelectric phase and the fabrication of unimorph has been made using high piezoelectric coefficient material showing higher peak to peak voltage generation of 2.5 V with much longer response time (6 ms) in stretched nanohybrid under an impulse load. Finally, the voltage and current output from the devices are measured under varying load and highest power density value of 25 mW/cm 3 is obtained for stretched nanohybrid, more than sufficient to operate a miniature self-powering device.Introduction:

Retracted Article: A bio-based piezoelectric nanogenerator for mechanical energy harvesting using nanohybrid of poly(vinylidene fluoride)

“…1d). 11,40 It is interesting to note that the a-phase peak intensity of pure PVDF considerably decreased in P-ESM, although there was no b-phase peak; this indicates decreased crystallinity in P-ESM, presumably due to the greater interaction between PVDF and ESM. The interaction was further visualized from the presence of carbonyl, amide and -OH groups in ESM (ESI Fig.…”

“…Moreover, the crystalline b-phase peak at $20.5 (corresponding to the 200/ 110 planes) was noted in the spectrum of the PC-ESM nanohybrid. There is a clear phase change from a to b in the presence of nanoclay (nanoclay-induced phase transformation), arising from the intimate interactions between the nanoclay and the PVDF chains, 11,38 while ESM alone was unable to induce b-phase in the polymer. It should be mentioned that ESM shows $40% crystalline phase (ESI Fig.…”

“…5,6 Mechanical energy from nger tapping, heel imparting, jogging, bending, joint movements, air ow, water ow, breathing and talking have been used for energy harvesting by several researchers. [7][8][9][10][11] Self-powered devices or nanogenerators harvest the mechanical energy from different sources. To date, many approaches have been proposed based on triboelectric 12 and piezoelectric 13,14 nanogenerators.…”

Functionalized Polyvinylidene Fluoride Electrospun Nanofibers and Applications

“…Although the piezoelectric coefficient of PVDF and its copolymers PVDF-HFP and PVDF-TrFE are less than piezoelectric ceramics like PBZ and BaTiO 3 , their elasticity and mechanical stretchability make them more reliable materials for several emerging applications [2]. Moreover, PVDF exhibits higher piezoelectric response voltage, good thermal stability, and chemical resistance suitable for sensors, aerosol filters, actuators, fuel cells, energy harvesters, and other applications [3][4][5][6][7].…”

Polarization of Electrospun PVDF Fiber Mats and Fiber Yarns

“…These materials find use in various industrial applications and are the topics of many contemporary academic research efforts. Of these materials, the polymer electrospun fibers have found broad uses for catalysis, drug delivery, semiconductors and filtration [1][2][3].…”