Hierarchically Structured Porous Piezoelectric Polymer Nanofibers for Energy Harvesting.

Mohammad Mahdi Abolhasani,Saleem Anwar,Jasper J Michels,Kamal Asadi,Minoo Naebe,Kamyar Shirvanimoghaddam,Morteza Hassanpour Amiri

doi:10.1002/advs.202000517

Abstract

Hierarchically porous piezoelectric polymer nanofibers are prepared through precise control over the thermodynamics and kinetics of liquid–liquid phase separation of nonsolvent (water) in poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) solution. Hierarchy is achieved by fabricating fibers with pores only on the surface of the fiber, or pores only inside the fiber with a closed surface, or pores that are homogeneously distributed in both the volume and surface of the nanofiber. For the fabrication of hierarchically porous nanofibers, guidelines are formulated. A detailed experimental and simulation study of the influence of different porosities on the electrical output of piezoelectric nanogenerators is presented. It is shown that bulk porosity significantly increases the power output of the comprising nanogenerator, whereas surface porosity deteriorates electrical performance. Finite element method simulations attribute the better performance to increased volumetric strain in bulk porous nanofibers.

Highlights

Porous piezoelectric polymer nanofibers are prepared through precise control over the thermodynamics and kinetics of liquid–liquid phase for variety of applications for instance in biomedicine,[2] CO2 capture,[3] filtration,[4] and vibrational piezoelectric energy separation of nonsolvent in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) solution
We show that while surface porosity deteriorates the performance of nanogenerators bulk porosity significantly increase the power output of the porous fibers by up to 280 times compared to reference P(VDF-TrFE) fibers
The hierarchical porosity within the electrospun mats is precisely designed by using the thermodynamics and kinetics of liquidliquid phase separation in the ternary mixture of P(VDF-TrFE), solvent (i.e., THF or DMF) and water

Summary

Introduction

Porous piezoelectric polymer nanofibers are prepared through precise control over the thermodynamics and kinetics of liquid–liquid phase for variety of applications for instance in biomedicine,[2] CO2 capture,[3] filtration,[4] and vibrational piezoelectric energy separation of nonsolvent (water) in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) solution. For the fabrication of hierarchically porous designing a robust process for the polymers nanofibers, guidelines are formulated. It is shown that bulk porosity significantly increases the power output of the comprising nanogenerator, whereas surface porosity deteriorates electrical performance. An experimentally well-established route to fabricate method simulations attribute the better performance to increased volumetric porous polymer films for membranes apstrain in bulk porous nanofibers. Porous polymer structures due to their large specific surface of the phase separation process. The thermodynamically unstable polymer solution is separated via a nucleation and growth mechanism (NG), while the spinodal decomposition (SD) is the mechanism dominating the phase separation process inside the unstable area.

Methods

Results

Conclusion