scholarly journals The Radial Piezoelectric Response from Three-Dimensional Electrospun PVDF Micro Wall Structure

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1368
Author(s):  
Guoxi Luo ◽  
Yunyun Luo ◽  
Qiankun Zhang ◽  
Shubei Wang ◽  
Lu Wang ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Three Dimensional ◽  
Piezoelectric Response ◽  
Wall Structure ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Β Phase ◽  
Piezoelectric Energy ◽  
Novel Structure ◽  
Random Arrangement

The ability of electrospun polyvinylidene fluoride (PVDF) fibers to produce piezoelectricity has been demonstrated for a while. Widespread applications of electrospun PVDF as an energy conversion material, however, have not materialized due to the random arrangement of fibers fabricated by traditional electrospinning. In this work, a developed 3D electrospinning technique is utilized to fabricate a PVDF micro wall made up of densely stacked fibers in a fiber-by-fiber manner. Results from X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR) demonstrate that the crystalline structure of this PVDF wall is predominant in the β phase, revealing the advanced integration capability of structural fabrication and piezoelectric poling with this 3D electrospinning. The piezoelectric response along the radial direction of these PVDF fibers is measured while the toppled micro wall, comprised of 60 fibers, is sandwich assembled with a pair of top/bottom electrodes. The measured electrical output is ca. 0.48 V and 2.7 nA. Moreover, after constant mechanical compression happening over 10,000 times, no obvious reduction in the piezoelectric response has been observed. The combined merits of high-precision 3D fabrication, in situ piezoelectric poling, and high mechanical robust make this novel structure an attractive candidate for applications in piezoelectric energy harvesting and sensing.

scholarly journals Effect of fabrication technique on the crystalline phase and electrical properties of PVDF films

2015 ◽  
Vol 33 (1) ◽  
pp. 157-162 ◽  
Author(s):  
P. K. Mahato ◽  
A. Seal ◽  
S. Garain ◽  
S. Sen
Keyword(s):  
Polyvinylidene Fluoride ◽  
Tape Casting ◽  
Dimethyl Formamide ◽  
Pvdf Film ◽  
X Ray Diffraction ◽  
Β Phase ◽  
Cast Films ◽  
Solvent Cast ◽  
Ft Ir ◽  
Ferroelectric Hysteresis

AbstractThe effect of different fabrication techniques on the formation of electroactive β-phase polyvinylidene fluoride (PVDF) has been investigated. Films with varying concentration of PVDF and solvent - dimethyl formamide (DMF) were synthesized by tape casting and solvent casting techniques. The piezoelectric β-phase as well as non polar β-phase were observed for both the tape cast and solvent cast films from X-ray diffraction (XRD) micrographs and Fourier transform infra-red spectroscopy (FT-IR) spectra. A maximum percentage (80 %) of β-phase was obtained from FT-IR analysis for a solvent cast PVDF film. The surface morphology of the PVDF films was analyzed by FESEM imaging. The dielectric properties as a function of temperature and frequency and the ferroelectric hysteresis loop as a function of voltage were measured. An enhancement in the value of the dielectric constant and polarization was obtained in solvent cast films.

Study on Novel Structure of Potassium Borate Hydrate: K(H4B5O10)·2(H2O)

2012 ◽  
Vol 531-532 ◽  
pp. 409-412
Author(s):  
Hai Xing Liu ◽  
Fang Fang Jian ◽  
Jing Wang ◽  
Guang Zeng ◽  
Hui Juan Yue ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potassium Borate ◽  
Polyhydroxy Compounds ◽  
Novel Structure ◽  
Solution Reaction

Numerous stable complexes of boric acid with polyhydroxy compounds, including tartaric, salicylic, citric, malic, and other acids, are known. The structure of some compounds contains polyanion. In this paper, a novel potassium borate hydrate [K(H4B5O10) •2(H2O)] has been synthesized from a solution reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. Orthorhombic, Aba2. a = 11.0781(14) Å b = 11.1780(15) Å c = 9.0508(11) Å α=β=γ=90°. V= 1120.8(2) Å3. Z=4. Rgt = 0.0244, wRref = 0.0623. T= 298 K. The crystal packing is stabilized by O-H...O hydrogen bonds interaction and three dimensional framwork structure is formed. The work is originality and has a new crystallographic structure shape.

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

2006 ◽  
Vol 514-516 ◽  
pp. 915-919 ◽  
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.

scholarly journals Static-Aligned Piezoelectric Poly (Vinylidene Fluoride) Electrospun Nanofibers/MWCNT Composite Membrane: Facile Method

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 965 ◽  
Author(s):  
Nader Shehata ◽  
Eman Elnabawy ◽  
Mohamed Abdelkader ◽  
Ahmed Hassanin ◽  
Mohamed Salah ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
High Speed ◽  
Vinylidene Fluoride ◽  
Electrospun Nanofibers ◽  
Piezoelectric Response ◽  
Rotating Drum ◽  
Β Phase ◽  
Aligned Nanofibers ◽  
Poly Vinylidene Fluoride ◽  
Nanofiber Mats

Polyvinylidene Fluoride (PVDF) piezoelectric electrospun nanofibers have been intensively used for sensing and actuation applications in the last decade. However, in most cases, random PVDF piezoelectric nanofiber mats have moderate piezoelectric response compared to aligned PVDF nanofibers. In this work, we demonstrate the effect of alignment conducted by a collector setup composed of two-metal bars with gab inside where the aligned fiber can be formed. That is what we called static aligned nanofibers, which is distinct from the dynamic traditional technique using a high speed rotating drum. The two-bar system shows a superior alignment degree for the PVDF nanofibers. Also, the effect of added carbon nanotubes (CNTs) of different concentrations to PVDF nanofibers is studied to observe the enhancement of piezoelectric response of PVDF nanofibers. Improvement of β-phase content of aligned (PVDF) nanofibers, as compared to randomly orientated fibers, is achieved. Significant change in the piezoelectricity of PVDF fiber is produced with added CNTs with saturation response in the case of 0.3 wt % doping of CNTs, and piezoelectric sensitivity of 73.8 mV/g with applied masses down to 100 g.

Characterization of Piezoelectric Properties of Ag-NPs Doped PVDF Nanocomposite Fibres Membrane Prepared by Near Field Electrospinning

2021 ◽  
Vol 24 ◽  
Author(s):  
Cheng-Tang Pan ◽  
Karishma Dutt ◽  
Chung-Kun Yen ◽  
Ajay Kumar ◽  
Aman Chandra Kaushik ◽  
...  
Keyword(s):  
Piezoelectric Material ◽  
Polyvinylidene Fluoride ◽  
Electrospun Fiber ◽  
Near Field ◽  
Piezoelectric Response ◽  
Large Area ◽  
Ag Nps ◽  
Electrospinning Technique ◽  
Sensing Applications ◽  
Wide Range

Background: In this study, Near-field electrospinning (NFES) technique used with a cylindrical collector to fabricate a large area permanent piezoelectric micro and nanofibers by a prepared solution. NFES requires a small electric field to fabricate fibers. Objective: The objective of this paper to investigate silver nanoparticle (Ag-NP)/ Polyvinylidene fluoride (PVDF) composite as the best piezoelectric material with improved properties to produced tremendously flexible and sensitive piezoelectric material with pertinent conductance. Method: In this paper we used controllable electrospinning technique based on Near-field electrospinning (NFES)The process parameter for Ag-NP/PVDF composite electrospun fiber based on pure PVDF fiber. A PVDF solution concentration of 18 wt.% and 6 wt.% silver nitrate which is relative to the weight of PVDF wt.% with 1058 µS conductivity fibers have been directly written on a rotating cylindrical collector for aligned fiber PVDF/Ag-NP fibers are patterned on fabricated copper (Cu) interdigitated electrodes were implemented on a thin flexible polyethylene terephthalate (PET) substrate and Polydimethylsiloxane (PDMS) used as a package to enhance the durability of the PVDF/ Ag-NP device. Results: A notable effect on the piezoelectric response has been observed after Ag-NP addition confirmed by XRD characterization and tapping test of Ag-NP/PVDF composite fiber. The morphology of the PVDF/Ag-NP fibers and measure diameter by scanning electron microscopy (SEM) and Optical micrograph (OM), of fiber. Finally, The result shows that diameter of PVDF/Ag-NP fibers up to ~7 μm. The. High diffraction peak at 2θ = 20.5˚ was investigated by X-ray diffraction (XRD) in the piezoelectric crystal β-phase structure. While the electromechanical conversion is found enhance from ~0.1 V to ~1 V by the addition of silver nanoparticles (Ag-NPs) in the PVDF solution. Conclusion: In conclusion, we can say that confirmed and validated the addition of Ag-NP in PVDF could enhance the piezoelectric property by using NFES technique with improved crystalline phase content can be useful for a wide range of power and sensing applications like biomedical devices and energy harvesting, among others.

Crystalinity Properties of Carbon Nanotube-Polyvinylidene Fluoride Composites

2008 ◽  
Vol 1134 ◽  
Author(s):  
Xiaobing Shan ◽  
Pei-xuan Wu ◽  
Lin Zhang ◽  
Zhong-Yang Cheng
Keyword(s):  
Differential Scanning Calorimetry ◽  
Carbon Nanotube ◽  
Acid Treatment ◽  
Polyvinylidene Fluoride ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Β Phase ◽  
Solution Cast ◽  
Solution Cast Method

AbstractSingle-wall and multi-wall carbon nanotube blends (0 to 0.5 vol% ) with polyvinylidene fluoride (PVDF) have been prepared using solution cast method and characterized. By acid treatment, it has been observed that nanotube has been well functionalized and uniformly dispersed into the polymer. X-ray diffraction analysis coupled with differential scanning calorimetry (DSC) has revealed that carbon nanotube alters the crystallinity of PVDF and thereby enhances the β-phase in PVDF. Experimental results have demonstrated that enhancement of β-phase is a function of carbon nanotube concentration.

The crystal structure of the first synthetic copper(II) tellurite arsenate, CuII 5(TeIVO3)2(AsVO4)2

2020 ◽  
Vol 76 (1) ◽  
pp. 1-6
Author(s):  
Owen P. Missen ◽  
Matthias Weil ◽  
Stuart J. Mills ◽  
Eugen Libowitzky
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Chemical Vapour ◽  
Structure Type ◽  
Void Space ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Structure ◽  
Jahn Teller ◽  
Transport Method

Crystals of the first synthetic copper tellurite arsenate, CuII 5(TeIVO3)2(AsVO4)2 [systematic name pentacopper(II) bis-oxotellurate(IV) bis-oxoarsenate(V)], were grown by the chemical vapour transport method and structurally determined using single-crystal X-ray diffraction. CuII 5(TeIVO3)2(AsVO4)2 possesses a novel structure type including a new topological arrangement of CuII and O atoms. CuII 5(TeIVO3)2(AsVO4)2 is formed from a framework of two types of Jahn–Teller distorted [CuIIO6] octahedra (one of which is considerably elongated) and [CuIIO5] square pyramids, which are linked by edge-sharing to form chains and dimers and by corner-sharing to complete a three-dimensional framework. [AsVO4] tetrahedra and [TeIVO5] polyhedra bridge the edges of channels along the a-axis direction, with void space remaining for the TeIV stereoactive 5s 2 lone pairs. A comparison is made between the crystal structure of CuII 5(TeIVO3)2(AsVO4)2 and those of known compounds and minerals, in particular fumarolitic Cu minerals.

Properties of PVDF films stretched in machine direction

2020 ◽  
pp. 096739112091059
Author(s):  
TS Roopa ◽  
HN Narasimha Murthy ◽  
DVN Harish ◽  
Anjana Jain ◽  
Gangadhar Angadi
Keyword(s):  
Electron Microscopy ◽  
Polyvinylidene Fluoride ◽  
Piezoelectric Properties ◽  
Gray Relational Analysis ◽  
X Ray Diffraction ◽  
Polar Solvents ◽  
Β Phase ◽  
Transmission Electron ◽  
Diffraction Peaks ◽  
Mechanical Stretching

Polyvinylidene fluoride (PVDF) films possess superior piezoelectric properties due to the β-phase obtained by methods, such as addition of nanofillers, application of high electric field, use of polar solvents and mechanical stretching. Simultaneous stretching and heating of the films can reduce porosity, increase transformation from α-phase to β-phase, and hence, improve their piezoelectric properties. This article presents the effects of stretching PVDF films on the β-phase formation and the resulting mechanical properties. A custom-designed stretching unit with roller mechanism and heating provision was employed for the purpose. The 200% stretched films at 100°C showed 86.79% β-phase, which is in correlation with X-ray diffraction peaks at 2 θ = 20.3–20.6°. Transmission electron microscopy and scanning electron microscopy of the stretched films revealed spherulitic to lamellar transformation and decrease in porosity. Stretching increased crystallinity from 32.99% to 44.84%. Nanoindentation results showed increase in hardness and Young’s modulus from 23.33 MPa to 93.3 MPa and 0.483 GPa to 1.816 GPa, respectively. Tensile strength increased from 4.72 MPa to 21.02 MPa. The experiments were conducted using L9 orthogonal array and the results were analyzed using analysis of variance and gray relational analysis.

Fabrication, Characterization and Investigation of Novel PVDF/ZnO and PVDF-TrFE/ZnO Nanocomposites with Enhanced β-Phase and Dielectricity

2020 ◽  
Vol 977 ◽  
pp. 277-282
Author(s):  
Ming Ran Liu
Keyword(s):  
Human Body ◽  
Polyvinylidene Fluoride ◽  
Pressure Sensors ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Zno Nanostructure ◽  
Β Phase ◽  
Arterial Blood ◽  
Sensing Material

To date, flexible, sensitive and biocompatible pressure sensors for fluctuation signals in human body have been mainly demonstrated for detecting body and muscle motion, pulse rate, heart rate and arterial blood pressure. However, because of the lack of sufficient sensitivity and flexibility, pulse signals with relatively low intensity cannot be identified and captured, such as signals derived from microcirculation in human body. As confirmed and validated by researchers, once PVDF and its copolymer based nanocomposite sensing material are applied in piezoelectric sensors, its sensitivity and piezoelectricity are highly relevant. Therefore, as one of the most effective methods to improve the permittivity and piezoelectricity of PVDF and its copolymer based nanocomposite, the effect of increasing the content of β-phase crystal was investigated in this work. In this project, the sensor possessing a novel sensing layer with the nanofiller was investigated and fabricated. The proposed sensor was designed in a simple but efficient sandwich structure. The sensing layer of the proposed sensor was made of polyvinylidene fluoride (PVDF) and polyvinylidenefluoride-trifluoroethylene (PVDF-TrFE) based nanocomposite with Zinc Oxide (ZnO) nanostructure acting as a filler portion which was fabricated by the method of Chemical Bath Deposition (CBD). The fabricated nanocomposite sensing layers were characterized. The microstructures and morphologies of pristine PVDF (P), PVDF-TrFE (PT), PVDF/ZnO (P/Z) and PVDF-TrFE/ZnO (PT/Z) with different concentration were characterized by Scanning Electron Microscope (SEM). The degree of crystallinity for P, PT, P/Z and PT/Z was obtained by X-ray Diffraction meter (XRD). In conclusion, PT exhibited better performance in both morphology and crystallinity as a sensing membrane material. More β‐phase in PT was obtained than that in P. ZnO, as a semiconductor filler, would have substantial influence on enhancing the dielectric constant by acting as a nucleating agent and forming a nanostructure with large aspect ratio.

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