Piezoelectricity Of PVDF Research Articles

Macroscopic Room-Temperature Magnetoelectricity in Piezoelectric (Core)-Ferrimagnetic (Shell) Nanocomposites.

The magnetoelectric (ME) effect, which involves the interaction of magnetic and electric fields within a material, has a significant potential for various applications. Our study addresses the limitations of conventional magnetostriction-based ME materials by demonstrating an alternative approach that achieves substantial ME effects in core-shell-type nanocomposites at room temperature. By synthesizing ferrimagnetic Fe3O4 nanoparticles onto piezoelectric poly(vinylidene fluoride) (PVDF) particles, we identified a distinct ME mechanism. In magnetorheological (MR) fluids, the magnetic-field-induced aggregation of Fe3O4 nanoparticles, combined with the piezoelectricity of PVDF, leads to a pronounced ME effect, significantly enhancing the performance and stability of MR fluids. This research highlights a crucial observation of distinct ME effects, which could suggest potential pathways for advancements in practical applications including microfluidics, vibration dampers, tactile technologies, and biomedical and bioengineering fields.

Largely enhanced Piezoelectric-Fenton capability in rationally designed PVDF/Fe2O3 flexible porous film

The burgeoning piezocatalysts have attracted huge attentions due to their ability to convert natural mechanical energy to degrade water pollutants. However, traditional powder-based piezocatalysts still face an inevitable bottleneck of the secondary pollution because of the diffusion of nanoparticles during the piezocatalysis process. In this work, novel porous polymer-based composite films combining Fenton fillers (α-Fe2O3) and ferroelectric polymer (polyvinylidene fluoride, PVDF) are prepared by rationally designed solution-casted method with a sacrificial “hard template” of table salt. The as-prepared porous PVDF/Fe2O3 film exhibits superior decomposition efficiency of organic pollutants under ultrasonication. Particularly, the easily recyclable porous film with optimized composition and spatial structure offers an ultrahigh rate constant of 0.0498 min−1, which means it can degrade 94.8% rhodamine B (RhB) in 60 min, exceeding that of most reported polymer-based piezocatalysts. Additionally, it has a comprehensive decomposition effect on dyes, antibiotics and natural water with a good cycle performance. The outstanding degradation performance is attributed to the massive hydroxyl radical generated from the enhanced Piezoelectric-Fenton effect, which is ascribed to the synergistic effect of improved piezoelectricity in PVDF, enhanced hydrophilicity and optimized spatial structures in the porous composite films.

A comprehensive review on poly(vinylidene fluoride) from a theoretical and multimodal applications perspective

AbstractWith the fast paced development of electronic devices in the past few decades, self powered, biocompatible, flexible small but easy to fabricate devices are becoming more and more desirable. Poly(vinylidene fluoride) (PVDF) and its co‐polymers are being used to make such devices because those devices have those characters. In this study we presented brief history regarding piezoelectricity in general and piezoelectricity in PVDF and its copolymers in particular. We have discussed the theoretical understanding about the piezoelectric properties in these piezoelectric materials and the unsolved open questions. We have presented many different applications of PVDF and its copolymers. Here, we tried to cover all the dimensions of study around PVDF and its copolymers. The intention here is to help anyone who wants to work on this field with an overall brief map of this field.Highlights This is a comprehensive review on the topic. Historical development of this field of research is discussed. Theoretical developments and the unsolved open questions are also included. Some of the important applications of piezoelectric polymers like P(VDF‐HFP) are discussed. Future direction of research in this field is also indicated.

Effects of stretching on phase transformation of PVDF and its copolymers: A review

Abstract Poly(vinylidene fluoride) (PVDF) and its copolymers are promising candidates for energy-harvesting devices because of their flexibility, environmental friendliness, lightweight, and high halogen and acid resistance. However, the relatively low piezoelectricity limits their applications. The piezoelectricity of PVDF and its copolymers highly depends on the polar β-phase, while the non-polar α-phase is the most common one. As a result, the β-phase formation and α- to β-phase transformation have attracted much attention in recent years. Stretching is a widely used method to induce the α- to β-phase transformation for the improvement of piezoelectricity. In this work, the influences of the parameters during stretching on phase evolution and piezoelectricity are discussed and summarized. Besides, nontraditional stretching methods are also introduced and discussed. This work will provide important information for preparing high-performance piezoelectric polymer films.

Polar Phase Formation and Piezoelectricity of PVDF by Hot-pressing under Electrostatic Intermolecular Interactions

Polar Phase Formation and Piezoelectricity of PVDF by Hot-pressing under Electrostatic Intermolecular Interactions

Enhanced Piezoelectric Performance of Various Electrospun PVDF Nanofibers and Related Self-Powered Device Applications.

The piezoelectric polymer poly(vinylidene fluoride) (PVDF) has been widely employed for energy harvesting or sensors. Its piezoelectricity originates from the unique crystal structure and the oriented electric dipoles. Generally, electrospinning (ES) is able to improve the crystallinity and piezoelectricity of PVDF. In this investigation, three types of ES, including far-field ES with random (R-PVDF-FFES) or aligned distribution (A-PVDF-FFES) and near-field ES (PVDF-NFES), are applied to fabricate a one-step polarized PVDF membrane. To compare the piezoelectricity of separated PVDF-NFES fibers, the array of PVDF-NFES fibers is encapsulated in polylactic acid (PLA). The result shows that the piezoelectricity of PVDF is dramatically enhanced by NFES and FFES. In d31 mode, the current density of PVDF-NFES-PLA is 75.63 pA cm-2 with a 2 Hz shear force, which is four times larger than A-PVDF-FFES (17.62 pA cm-2) or seven times larger than R-PVDF-FFES (10.63 pA cm-2). Due to its outstanding property, the PVDF-NFES-PLA membrane is designed to be applied as a self-powered device. The unimorph cantilevers are prepared to harvest the vibration energy and their output power density reaches 95.3 μW m-2 at a resonance frequency of 31 Hz. Meanwhile, the flexible bending sensor and pressure sensor are fabricated with a PVDF-NFES-PLA membrane, which shows the stable response for pressure with sensitivity values of 864.68 and 22.6 mV kPa-1, respectively.

Piezoelectricity in PVDF and PVDF Based Piezoelectric Nanogenerator: A Concept

Piezoelectricity in PVDF and PVDF Based Piezoelectric Nanogenerator: A Concept

Piezoelectric electrospun nanocomposite comprising Au NPs/PVDF for nerve tissue engineering.

In this study, gold nanoparticles/Polyvinylidenefluoride (PVDF) composite electrospun mat with enhanced piezoelectricity were fabricated and characterized. Gold colloidal nanoparticles (Au NPs) were prepared via laser ablation of metallic targets in liquid media. The active Q-switched Nd:YAG laser was used as an irradiation source. Then, PVDF was dissolved in Au NPs colloidal solution at 30% wt for the synthesis of Au NPs/PVDF composite nanofibers by electrospinning. The optical absorbance spectra of Au NPS and the polymeric solutions were obtained by the UV-Visible spectroscopy. Moreover, the morphology of Au NPS, nanostructures of fibers and diameter size distribution of nanofibers were analyzed by Scanning Electron Microscopy, Field Emission Scanning Electron Microscopy, and Transmitted Electron Microscopy methods. The crystallinity and piezoelectricity of PVDF and Au NPs/PVDF composite nanofibers mats were measured by X-Ray Diffraction and Fourier Transform Infrared methods. Subsequently, in vitro cytocompatibility was evaluated by MTT assay and the attachment and morphology of PC-12 cells cultured on scaffolds were studied. It was found that laser ablated Au NPs can be used in electrospun nanofibers of PVDF with adequate structural properties and increase piezoelectricity of nanofibers which might be suitable for applying as nerve tissue engineering scaffolds. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1984-1993, 2017.

Structural impact on piezoelectricity in PVDF and P(VDF-TrFE) thin films

PVDF and its mostly used copolymer P(VDF-TrFE) are known to possess piezoelectric properties which strongly vary with processing conditions. As the final target of processing ultimately is the structure of the polymer, establishing a more detailed link between structure and properties would ease both the understanding and the practical usage of films piezoelectric activity. In spite of a number of thorough studies exploiting the nature of piezoelectricity in PVDF, available data does not generally exhibit reliable level of consistency and, in some cases, elements of contradiction are observed. Making no claim to be exhaustive in this vast area, we present a survey and discuss on a number of results both available and obtained by ourselves in an effort to assist to better interpretation and further progress in the field.

The days when piezoelectric PVDF was discovered

Abstract It was around 1970 when the piezoelectricity of PVDF was discovered by Dr. Heiji Kawai.1 In those days Kawai was at Kobayasi Institute of Physical Research before moving to Yokohama City University, and I was at the University of Electro-Communications and held also the post of consultant researcher at Kobayasi Institute, thus I was able to observe Kawai's discovery with my own eyes.

Physical basis for piezoelectricity in PVDF

Abstract Consideration of the molecular and bulk structures of PVDF and related semicrystalline polymers, and the effects of processing to make transducer films, leads to a novel way of analysing the elastic and piezoelectric constant data. The results of this analysis support the conclusion that thickness changes contribute about 2/3 of the piezoelectric activity. An increase in thickness decreases the charge on the electrodes. The probable mechanism is simply the displacement of the electrodes in the fields of the constant dipole moments of the crystals. The remaining 1/3 of the activity is attributed to changes in the film's dipole moment at constant thickness. Strains in the orientation direction of the film increase the charge on the surface while strains in the plane of the film normal to the orientation direction decrease it. Eight separate possible contributions to the change in moment are discussed, and qualitative evaluations of their importance are given.

Surface effects in corona-charged polyvinylidene fluoride

Biaxially oriented films of polyvinylidene fluoride [-(CH2-CF2) n -...; PVDF] of thickness 25 μm, originally containing both the α and β crystal forms, have been corona charged at room temperature to surface potentials of up to 10 kV using positive and negative corona. The behaviour of the optical density of the α-form infra-red band at 796 cm−1, measured in the transmission mode, was found to be inverse to that of the piezoelectric coefficient, g31, with increasing charging voltage. Attenuated total reflection (ATR) measurements on the same samples indicated that the extent of poling close to the surface which received the corona charge was less than that close to the earthed surface and less than that of the bulk. The results support a mechanism of dipole orientation for the origin of piezoelectricity in PVDF.