Electrospun PVDF-based piezoelectric nanofibers: materials, structures, and applications

Abstract

Polyvinylidene fluoride (PVDF) has been considered as a promising piezoelectric material for advanced sensing and energy storage systems because of its high dielectric constant and good electroactive response. Electrospinning is a straightforward, low cost, and scalable technology that can be used to create PVDF-based nanofibers with outstanding piezoelectric characteristics. Herein, we summarize the state-of-the-art progress on the use of filler doping and structural design to enhance the output performance of electrospun PVDF-based piezoelectric fiber films. We divide the fillers into single filler and double fillers and make comments on the effects of various dopant materials on the performance and the underlying mechanism of the PVDF-based piezoelectric fiber film. The effects of highly oriented structures, core-shell structures, and multilayer composite structures on the output properties of PVDF-based piezoelectric nanofibers are discussed in detail. Furthermore, the perspectives and opportunities for PVDF piezoelectric nanofibers in the fields of health care, environmental monitoring, and energy collection are also discussed.

Fig. 1. Materials, structures, and applications of electrospun PVDF-based piezoelectric nanofiber films. (Go clockwise from double fillers: reproduced from ref. with permission from the American Chemical Society, copyright 2019. Reproduced from ref. with permission from Elsevier Ltd, copyright 2020. Reproduced from ref. with permission from the MDPI, copyright 2018. Reproduced from ref. with permission from the Chongqing University, copyright 2021. Reproduced from ref. with permission from the Elsevier B.V., copyright 2020. Reproduced from ref. with permission from the Elsevier B.V., copyright 2020. Reproduced from ref. with permission from the American Chemical Society, copyright 2020. Reproduced from ref. with permission from the American Chemical Society, copyright 2019).

Fig. 2. Electrospun PVDF-based single-filler nanofiber films: (a) schematic of the proposed mechanism for the electrospinning of pure PVDF, ZP30/PVDF, ZR5/PVDF composite fibers. Reproduced from ref. with permission from the American Chemical Society, copyright 2019. (b) Three-dimensional molecular model of the β-phase formation during the electrospinning process. Reproduced from ref. with permission from the Elsevier Ltd, copyright 2020. (c) Interaction mechanism between talc nanosheets and PVDF chain in electrospinning nanocomposite fabric. Reproduced from ref. with permission from the Royal Society of Chemistry, copyright 2020.

Fig. 3. Electrospun PVDF-based nanofiber films with two fillers: (a) fabrication of electrospun PVDF/KNN/ZnO web. Reproduced from ref. with permission from John Wiley & Sons, Inc., copyright 2020. (b) Mechanical stretching effect of the electrospun fiber in the presence of CNTs and β-nucleating effect of the CNTs in the PVDF polymer matrix. Reproduced from ref. with permission from the Royal Society of Chemistry, copyright 2020. (c) The mechanism diagram of β phase formation on BaTiO₃ NPs and graphene nanosheets in the nanocomposite fiber. Reproduced from ref. with permission from Elsevier Ltd, copyright 2018. (d) Comparison between unmodified and modified electrospun fibers via dopamine coating. Scale bar is 1 μm. Reproduced from ref. with permission from John Wiley & Sons, Inc., copyright 2021.

Fig. 4. Electrospun highly oriented PVDF-based nanofiber films: (a) piezoelectric properties of electrospun oriented PVDF fiber film. Reproduced from ref. with permission from John Wiley & Sons, Inc., copyright 2020. (b) Aligned PVDF-TrFE nanofibers for enhanced piezoelectric directional strain sensing. Reproduced from ref. with permission from the MDPI, copyright 2018. (c) Aligned electrospun PVDF/CNT nanofibers collected by a two-bar system. Reproduced from ref. with permission from the MDPI, copyright 2018.

Fig. 5. Electrospun core–shell structured PVDF-based nanofiber films: (a) PVDF-BaTiO₃/PVDF-GO piezoelectric nanofiber film. Reproduced from ref. with permission from Elsevier Ltd, copyright 2020. (b) Piezoelectric properties of (PVDF-HFP)-TiO₂/PVDF-ZnO nanofiber film. Reproduced from ref. with permission from the MDPI, copyright 2020. (c) PVDF/SF coaxial piezoelectric nanofiber film. Reproduced from ref. with permission from Chongqing University, copyright 2021. (d) PVDF/HHE coaxial piezoelectric nanofiber film. Reproduced from ref. with permission from the American Chemical Society, copyright 2019.

Fig. 6. Electrospun PVDF-based nanofiber films with a multilayer structure: (a) multilayer assembled electrospun nanofiber mats and their piezoelectric properties. Reproduced from ref. with permission from the American Chemical Society, copyright 2018. (b) Multilayer assembly of electrospun/electrosprayed PVDF-based nanofibers and beads. Reproduced from ref. with permission from Elsevier B.V., copyright 2020. (c) Flexible PVDF/BaTiO₃ hybrid-structure pressure sensor. Reproduced from ref. with permission from the Royal Society of Chemistry, copyright 2020. (d) PVDF-based multilayer composite. Reproduced from ref. with permission from Elsevier B.V., copyright 2015.

Fig. 7. Application of electrospun PVDF-based nanofiber films in medical and health fields: (a) PVDF/HHE sensor for real-time micropressure monitoring of cardiovascular walls. Reproduced from ref. with permission from the American Chemical Society, copyright 2019. (b) Wearable sensor prepared from the PVDF/BiCl₃/ZnO nanofiber film used for the detection of the bending and stretching of the left arm and left leg. Reproduced from ref. with permission from Elsevier Ltd, copyright 2021. (c) PVDF-HFP/ZnO composite nanofiber-based highly sensitive piezoelectric sensor for wireless workout monitoring. Reproduced from ref. with permission from the Springer Nature Switzerland AG, copyright 2021. (d) PVDF/PDA@BaTiO₃ wearable pressure sensor used to monitor physiological signals. Reproduced from ref. with permission from the Elsevier John Wiley & Sons, Inc., copyright 2021. (e) MMG sensors prepared using electrospun PVDF piezoelectric nanofibers for lower limb rehabilitation exoskeleton. Reproduced from ref. with permission from Elsevier B.V., copyright 2019.

Fig. 8. Application of electrospun PVDF-based nanofiber films in the environmental monitoring field: (a) flexible PVDF/BaTiO₃ pressure sensor used to monitor the weak vibration of the speaker. Reproduced from ref. with permission from the American Chemical Society, copyright 2020. (b) PVDF/graphene composite nanofibers for fabrication of nanopressure sensors and ultrasensitive acoustic nanogenerators. Reproduced from ref. with permission from the American Chemical Society, copyright 2016. (c) A flow velocity measurement method based on a PVDF piezoelectric sensor. Reproduced from ref. with permission from the MDPI, copyright 2019. (d) PVDF-TrFE/MXene sensor used to monitor ambient humidity. Reproduced from ref. with permission from Elsevier Ltd, copyright 2020. (e) The device prepared by PVDF/PI nanofiber film used for humidity sensing. Reproduced from ref. with permission from Elsevier Ltd, copyright 2020.

Fig. 9. Application of electrospun PVDF-based nanofiber films in the energy harvesting field: (a) PENG prepared from the PVDF/SM-KNN nanocomposite piezoelectric material. Reproduced from ref. with permission from Elsevier Ltd, copyright 2020. (b) PVDF nanofibers with embedded PANI-graphitic carbon nitride nanosheet composites for piezoelectric energy conversion. Reproduced from ref. with permission from the American Chemical Society, copyright 2019. (c) High-performance TENG based on MXene functionalized PVDF composite nanofibers. Reproduced from ref. with permission from Elsevier Ltd, copyright 2020. (d) PVDF/Co-NPC nanofiber films for a high-performance TENG. Reproduced from ref. with permission from Elsevier Ltd, copyright 2022. (e) Electrospun PVDF-HFP/LM nanofiber film with exceptional triboelectric performance. Reproduced from ref. with permission from Elsevier Ltd, copyright 2021.

Mengdi Zhang

Chengkun Liu

Boyu Li

Liang Wei

Runjun Sun

Fenglei Zhou