Direct piezoelectric response of piezopolymer polyvinylidene fluoride under high mechanical strain and stress

Bone exhibits piezoelectric properties. Thus, electrical stimulations such as pulsed electromagnetic fields (PEMFs) and stimuli-responsive piezoelectric properties of scaffolds have been investigated separately to evaluate their efficacy in supporting osteogenesis. However, current understanding of cells responding under the combined influence of PEMF and piezoelectric properties in scaffolds is still lacking. Therefore, in this study, we fabricated piezoelectric scaffolds by functionalization of polycaprolactone-tricalcium phosphate (PCL-TCP) films with a polyvinylidene fluoride (PVDF) coating that is self-polarized by a modified breath-figure technique. The osteoinductive properties of these PVDF-coated PCL-TCP films on MC3T3-E1 cells were studied under the stimulation of PEMF. Piezoelectric and ferroelectric characterization demonstrated that scaffolds with piezoelectric coefficient d33 = −1.2 pC/N were obtained at a powder dissolution temperature of 100 °C and coating relative humidity (RH) of 56%. DNA quantification showed that cell proliferation was significantly enhanced by PEMF as low as 0.6 mT and 50 Hz. Hydroxyapatite staining showed that cell mineralization was significantly enhanced by incorporation of PVDF coating. Gene expression study showed that the combination of PEMF and PVDF coating promoted late osteogenic gene expression marker most significantly. Collectively, our results suggest that the synergistic effects of PEMF and piezoelectric scaffolds on osteogenesis provide a promising alternative strategy for electrically augmented osteoinduction. The piezoelectric response of PVDF by PEMF, which could provide mechanical strain, is particularly interesting as it could deliver local mechanical stimulation to osteogenic cells using PEMF.

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Tunable In Situ 3D-Printed PVDF-TrFE Piezoelectric Arrays

Sensors ◽

10.3390/s21155032 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5032

Author(s):

Alec Ikei ◽

James Wissman ◽

Kaushik Sampath ◽

Gregory Yesner ◽

Syed N. Qadri

Keyword(s):

3D Printing ◽

Polyvinylidene Fluoride ◽

Vinylidene Fluoride ◽

Mechanical Strain ◽

Pressure Sensors ◽

Strain Ratio ◽

Ex Situ ◽

Order Of Magnitude ◽

3D Printed

In the functional 3D-printing field, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has been shown to be a more promising choice of material over polyvinylidene fluoride (PVDF), due to its ability to be poled to a high level of piezoelectric performance without a large mechanical strain ratio. In this work, a novel presentation of in situ 3D printing and poling of PVDF-TrFE is shown with a d33 performance of up to 18 pC N−1, more than an order of magnitude larger than previously reported in situ poled polymer piezoelectrics. This finding paves the way forward for pressure sensors with much higher sensitivity and accuracy. In addition, the ability of in situ pole sensors to demonstrate different performance levels is shown in a fully 3D-printed five-element sensor array, accelerating and increasing the design space for complex sensing arrays. The in situ poled sample performance was compared to the performance of samples prepared through an ex situ corona poling process.

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Electromechanical Coupling of PZT Nanofibers

Volume 13: Nano-Manufacturing Technology; and Micro and Nano Systems, Parts A and B ◽

10.1115/imece2008-68982 ◽

2008 ◽

Author(s):

Shiyou Xu ◽

Yong Shi

Keyword(s):

Forced Vibration ◽

Output Voltage ◽

Electromechanical Coupling ◽

Mechanical Strain ◽

Electrospinning Process ◽

Piezoelectric Response ◽

Vibration Source ◽

Titanium Film ◽

Three Point Bending ◽

Vibration Tests

This paper presented the results of electromechanical characterization of PZT nanofibers through applied mechanical strain and forced vibration. PZT nanofibers were fabricated by electrospinning process. Titanium film with ZrO2 layer was used to collect the nanofibers and also used as the substrates of the test coupons for the bending tests. Mechanical strain was applied to the test coupons through three-point-bending using Dynamic Mechanical Analyzer (DMA). The largest output voltage was 170mV under 0.5% applied strain. Silicon substrate with trenches was also used to collect the PZT nanofibers for the forced vibration tests. The output voltage from 150Hz sinusoid vibration source was also measured. The peaks of the output voltage were 64.9mV and −95.9mV, respectively. These tests have demonstrated the piezoelectric response of PZT nanofibers. Further tests are to be conducted to precisely determine the piezoelectric constants of PZT nanofibers.

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FLEXOELECTRIC COMPOSITE — A NEW PROSPECT FOR LEAD-FREE PIEZOELECTRICS

Functional Materials Letters ◽

10.1142/s1793604710000968 ◽

2010 ◽

Vol 03 (01) ◽

pp. 79-81 ◽

Cited By ~ 10

Author(s):

BAOJIN CHU ◽

WENYI ZHU ◽

NAN LI ◽

L. ERIC CROSS

Keyword(s):

Piezoelectric Properties ◽

Piezoelectric Materials ◽

Physical Phenomenon ◽

Mechanical Strain ◽

Dielectric Materials ◽

Electric Polarization ◽

Lead Free ◽

Piezoelectric Response ◽

Bst Ceramics ◽

Better Than

Flexoelectricity describes the physical phenomenon of the generation of electric polarization from mechanical strain gradient in solid insulators. In common dielectric materials, the flexoelectric coefficient is trivially small ~10-10 C/m. In Ba(Sr,Ti)O 3 (BST) ceramics, flexoelectric coefficient up to 10-4 C/m was observed. Such high coefficient makes it possible to design high piezoelectric response flexoelectric composites. In this letter, we will demonstrate that the newly designed flexoelectric composites could have piezoelectric properties better than conventional piezoelectric materials.

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Polyvinylidene fluoride (PVDF) as a feedstock for material extrusion additive manufacturing

Rapid Prototyping Journal ◽

10.1108/rpj-08-2018-0203 ◽

2020 ◽

Vol 26 (1) ◽

pp. 156-163 ◽

Cited By ~ 1

Author(s):

Niknam Momenzadeh ◽

Hadi Miyanaji ◽

Daniel Allen Porter ◽

Thomas Austin Berfield

Keyword(s):

Additive Manufacturing ◽

Polyvinylidene Fluoride ◽

Mechanical Response ◽

Dimensional Accuracy ◽

Piezoelectric Response ◽

Content Type ◽

Material Extrusion ◽

Deposition Parameters ◽

The Individual ◽

Deposition Conditions

Purpose This study aims to investigate the material extrusion additive manufacturing (MEAM) deposition parameters for creating viable 3-D printed polyvinylidene fluoride (PVDF) structures with a balanced mix of mechanical and electrical properties. Design/methodology/approach Different combinations of deposition conditions are tested, and the influence of these parameters on the final dimensional accuracy, semi-crystalline phase microstructure and effective mechanical strength of MEAM homopolymer PVDF printed parts is experimentally assessed. Considering printed part integrity, appearance, print time and dimensional accuracy, MEAM parameters for PVDF are suggested. Findings A range of viable printing parameters for MEAM fabricated PVDF Kynar 740 objects of different heights and in-plane length dimensions was determined. For PVDF structures printed under the suggested conditions, the mechanical response and the microstructure development related to Piezoelectric response are reported. Originality/value This research first reports on a range of parameters that have been confirmed to facilitate effective MEAM printing of 3-D PVDF objects, presents effects of the individual parameters and gives the mechanical and microstructure properties of PVDF structures fabricated under the suggested deposition conditions.

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Studies on the nonlinear piezoelectric response of polyvinylidene fluoride

Journal of Applied Physics ◽

10.1063/1.334528 ◽

1985 ◽

Vol 57 (4) ◽

pp. 1294-1298 ◽

Cited By ~ 32

Author(s):

Bernd R. Hahn

Keyword(s):

Polyvinylidene Fluoride ◽

Piezoelectric Response

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A Historical Perspective on the Occurrence of Piezoelectricity in Materials

MRS Bulletin ◽

10.1557/s0883769400063405 ◽

1989 ◽

Vol 14 (2) ◽

pp. 22-31 ◽

Cited By ~ 1

Author(s):

P.E. Dunn ◽

S.H. Carr

Keyword(s):

Dipole Moment ◽

Piezoelectric Effect ◽

Common Factor ◽

Mechanical Strain ◽

Piezoelectric Response ◽

Mechanical Pressure ◽

Naturally Occurring ◽

Induced Dipole ◽

Device Applications ◽

External Forces

This article provides an overview of the piezoelectric effect in all the classes of materials in which it is found to occur. This includes select materials from the categories of naturally occurring single crystals, polycrystalline ceramics, and semicrystalline polymers. Throughout this development, an attempt is made to point out the common factor for the piezoelectric effect in all these materials, namely, the presence of dipolar moieties, whose orientation brings about a net polarization in the material as a whole.The applications of each of these classes of materials are covered briefly. Each such application has a specific value based on the aggregate properties of the material as a whole, making each material complementary rather than competitive in device applications.Brief mention is made of the mathematics and geometry of the piezoelectric effect in order to define the piezoelectric constants by which the properties of these materials are described. The article then focuses on the basis of the piezoelectric response in synthetic polymers.Piezoelectricity or “pressure electricity” was coined from the Greek verb “piezen,” to press, by Pierre and Jacques Curie in the 1880s during an investigation of the symmetry in crystals. In this work it was found that certain crystals, lacking a center of symmetry, produced an electrical charge when mechanically deformed. The converse effect was also found to occur, whereby applying an electric field caused the crystal to change its shape. This phenomenon was attributed to a deformation of the net internal polarization in the crystal. When no external forces are present, the centers of positive and negative charges will coincide, and there is no net polarization. The application of a stress, be it mechanical (pressure) or electrical (applied field), causes a displacement of the centers of gravity of the positive and negative charges. In the absence of a center of symmetry, the charge displacement will be nonsymmetrical and thereby produce an induced dipole moment. This dipole moment, if produced by a mechanical stress, will cause the surfaces to develop an effective charge. If an external field displaces the charges, by electrostatic attraction or repulsion, it produces a mechanical strain which causes the material to deform. The mathematical relations describing this effect were developed in the few years following their discovery, making use of tensor notation to describe the directionality of the applied stress and the resultant strain.

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Composites, Fabrication and Application of Polyvinylidene Fluoride for Flexible Electromechanical Devices: A Review

Micromachines ◽

10.3390/mi11121076 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1076

Author(s):

Shuaibing Guo ◽

Xuexin Duan ◽

Mengying Xie ◽

Kean Chin Aw ◽

Qiannan Xue

Keyword(s):

Polyvinylidene Fluoride ◽

Piezoelectric Coefficient ◽

Piezoelectric Materials ◽

Technological Development ◽

High Hardness ◽

High Sensitivity ◽

Inorganic Materials ◽

Piezoelectric Response ◽

Practical Applications ◽

Electromechanical Devices

The technological development of piezoelectric materials is crucial for developing wearable and flexible electromechanical devices. There are many inorganic materials with piezoelectric effects, such as piezoelectric ceramics, aluminum nitride and zinc oxide. They all have very high piezoelectric coefficients and large piezoelectric response ranges. The characteristics of high hardness and low tenacity make inorganic piezoelectric materials unsuitable for flexible devices that require frequent bending. Polyvinylidene fluoride (PVDF) and its derivatives are the most popular materials used in flexible electromechanical devices in recent years and have high flexibility, high sensitivity, high ductility and a certain piezoelectric coefficient. Owing to increasing the piezoelectric coefficient of PVDF, researchers are committed to optimizing PVDF materials and enhancing their polarity by a series of means to further improve their mechanical–electrical conversion efficiency. This paper reviews the latest PVDF-related optimization-based materials, related processing and polarization methods and the applications of these materials in, e.g., wearable functional devices, chemical sensors, biosensors and flexible actuator devices for flexible micro-electromechanical devices. We also discuss the challenges of wearable devices based on flexible piezoelectric polymer, considering where further practical applications could be.

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Gas Sensing and Power Harvesting Polyvinylidene Fluoride Nanocomposites Containing Hybrid Nanotubes

Journal of Electronic Materials ◽

10.1007/s11664-019-07915-y ◽

2020 ◽

Vol 49 (4) ◽

pp. 2677-2687 ◽

Cited By ~ 1

Author(s):

Deepalekshmi Ponnamma ◽

Ashok K. Sharma ◽

Priya Saharan ◽

Mariam Al Ali Al-Maadeed

Keyword(s):

Polyvinylidene Fluoride ◽

Gas Sensing ◽

Response Times ◽

Hydrothermal Reaction ◽

Nanocomposite Films ◽

Piezoelectric Response ◽

Filler Materials ◽

Liquefied Petroleum Gas ◽

Self Powered ◽

The Stability

AbstractGas sensing properties at room temperature and energy harvesting performances are realized for the polyvinylidene fluoride (PVDF) nanocomposites containing titanium dioxide (TiO2) nanotubes grown in the presence of carbon nanotubes (CNT). While hydrothermal reaction is practiced for the development of TiO2/CNT hybrid nanotubes, spin coating is done for the nanocomposite films to be deposited on sensing electrodes. Influence of various filler concentrations and the synergistic combination of fillers on the sensing characteristics are studied by recording the response times and the stability of the results. Upon exposure to liquefied petroleum gas, the PVDF/TiO2-CNT (2.5 wt.%) gas sensor shows a sensing response of 0.45 s (400 ppm LPG), approximately nine times higher than the composite containing 2.5 wt.% of TiO2 or 2.5 wt.% CNT. The piezoelectric response of the samples is also recorded and correlated with the synergistic influence of the filler materials. The current study can stimulate a good trend in fabricating self-powered gas sensors from PVDF nanocomposites.

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Electrical and Microstructural Changes of β-PVDF under Uniaxial Stress Studied by Scanning Force Microscopy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.915 ◽

2006 ◽

Vol 514-516 ◽

pp. 915-919 ◽

Cited By ~ 7

Author(s):

Jivago Serrado-Nunes ◽

Vitor Sencadas ◽

Ai Ying Wu ◽

Paula M. Vilarinho ◽

Senentxu Lanceros-Méndez

Keyword(s):

Polyvinylidene Fluoride ◽

Strain Curve ◽

Scanning Force Microscopy ◽

Uniaxial Stress ◽

Piezoelectric Response ◽

Practical Applications ◽

Force Microscopy ◽

Β Phase ◽

Scanning Force ◽

Yielding Point

Chain reorientation may be induced in polyvinylidene fluoride (PVDF) in its β-phase by applying a deformation perpendicular to the pre-oriented polymeric chains. This reorientation begins right after the yielding point and seems to be completed when the stress-strain curve stabilizes. As the deformation process plays an important role in the processing and optimisation properties of the material for practical applications, different deformation stress was applied to the PVDF lamellas and their topographic change and piezoelectric response were studied by means of scanning force microscopy in a piezo-response mode. The experimental results confirm the previously observed chain reorientation that occurs right after the yielding point and that is completed when the yielding region is passed. This reorientation is accompanied by a stretching of the granular structures observed in the topographical images and variations in the domain response. The observed results help to explain the variations in the macroscopic response of the material.

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