Interfacial piezoelectric polarization locking in printable Ti3C2Tx MXene-fluoropolymer composites

Nick A Shepelin,Joselito M Razal,Ken Aldren S Usman,Jizhen Zhang,Joseph G Shapter,Eirini Goudeli,Peter C Sherrell,Amanda V Ellis,Emmanuel N Skountzos,Vanessa C Lussini,Beenish Imtiaz,Greg W Dicinoski

doi:10.1038/s41467-021-23341-3

Abstract

Piezoelectric fluoropolymers convert mechanical energy to electricity and are ideal for sustainably providing power to electronic devices. To convert mechanical energy, a net polarization must be induced in the fluoropolymer, which is currently achieved via an energy-intensive electrical poling process. Eliminating this process will enable the low-energy production of efficient energy harvesters. Here, by combining molecular dynamics simulations, piezoresponse force microscopy, and electrodynamic measurements, we reveal a hitherto unseen polarization locking phenomena of poly(vinylidene fluoride–co–trifluoroethylene) (PVDF-TrFE) perpendicular to the basal plane of two-dimensional (2D) Ti3C2Tx MXene nanosheets. This polarization locking, driven by strong electrostatic interactions enabled exceptional energy harvesting performance, with a measured piezoelectric charge coefficient, d33, of −52.0 picocoulombs per newton, significantly higher than electrically poled PVDF-TrFE (approximately −38 picocoulombs per newton). This study provides a new fundamental and low-energy input mechanism of poling fluoropolymers, which enables new levels of performance in electromechanical technologies.

Highlights

Piezoelectric fluoropolymers convert mechanical energy to electricity and are ideal for sustainably providing power to electronic devices
Electrical poling is energy-intensive, with electric fields on the order of tens to hundreds of megavolts per meter commonly used (Fig. 1b, c)[3,4,5]. In fluoropolymers such as poly (PVDF), a class of semicrystalline linearchain polymers exhibiting a dipole moment between the hydrogen and fluorine moieties perpendicular to the carbon backbone (Fig. 1a), the poling process requires elevated temperature conditions[3,4,6]
We employ molecular dynamics (MD) simulations to probe the evolution of the polarization of PVDF-TrFE in relation to the Ti3C2Tx nanosheet, revealing that the electrostatic interactions between the Ti3C2Tx nanosheet and the fluoropolymer are crucial to achieve effective induced local polarization locking. We extend this induced local polarization locking to a macroscale net polarization using solvent-evaporation assisted (SEA) 3D printing to impart enhanced shear alignment[8,29]

Summary

Introduction

Piezoelectric fluoropolymers convert mechanical energy to electricity and are ideal for sustainably providing power to electronic devices. By combining molecular dynamics simulations, piezoresponse force microscopy, and electrodynamic measurements, we reveal a hitherto unseen polarization locking phenomena of poly(vinylidene fluoride–co–trifluoroethylene) (PVDF-TrFE) perpendicular to the basal plane of two-dimensional (2D) Ti3C2Tx MXene nanosheets This polarization locking, driven by strong electrostatic interactions enabled exceptional energy harvesting performance, with a measured piezoelectric charge coefficient, d33, of −52.0 picocoulombs per newton, significantly higher than electrically poled PVDFTrFE (approximately −38 picocoulombs per newton). Electrical poling is energy-intensive, with electric fields on the order of tens to hundreds of megavolts per meter commonly used (Fig. 1b, c)[3,4,5] In fluoropolymers such as poly (vinylidene fluoride) (PVDF), a class of semicrystalline linearchain polymers exhibiting a dipole moment between the hydrogen and fluorine moieties perpendicular to the carbon backbone (Fig. 1a), the poling process requires elevated temperature conditions[3,4,6]. It has out-of-plane polarizability[21] with symmetry perpendicular to the basal plane[23,28] and is hypothesized to not possess out-ofplane piezoelectric properties

Methods

Results

Conclusion