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Piezoelectric and Electrostatic Properties of Electrospun PVDF‐TrFE Nanofibers and their Role in Electromechanical Transduction in Nanogenerators and Strain Sensors
Author(s) -
Calavalle Francesco,
Zaccaria Marco,
Selleri Giacomo,
Cramer Tobias,
Fabiani Davide,
Fraboni Beatrice
Publication year - 2020
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.202000162
Subject(s) - materials science , electrospinning , nanofiber , piezoelectricity , electret , ferroelectricity , ferroelectric polymers , electric field , composite material , piezoresponse force microscopy , polymer , nanotechnology , optoelectronics , dielectric , physics , quantum mechanics
Piezo‐ and ferroelectric nanofibers of the polymer poly(vinylidenefluoride) (PVDF) have been widely employed in strain and pressure sensors as well as nanogenerators for energy harvesting. Despite this interest, the mechanism of electromechanical transduction is under debate and a deeper knowledge about relevant piezoelectric or electrostatic properties of nanofibers is crucial to optimize transduction efficiency. Here poly(vinylidenefluoride‐trifluoroethylene) nanofibers at different electrospinning conditions are prepared. Macroscopic electromechanical response of fiber mats with microscopic analysis of single nanofibers performed by piezoelectric and electrostatic force microscopy are compared. The results show that electrospinning favors the formation of the piezoelectric β‐phase in the polymer and leads directly to piezoelectric properties that are comparable to annealed thin films. However, during electrospinning the electric field is not strong enough to induce direct ferroelectric domain polarization. Instead accumulation of triboelectric surface charges and trapped space charge is observed in the polymer that explain the electret like macroscopic electromechanical response.