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.

Stretching Induced Crystalline-Phase Transition in Energy-Conversion Poly(Vinylidene Fluoride) (PVDF) Films

2014 ◽  
Vol 1070-1072 ◽  
pp. 589-593
Author(s):  
Fei Peng Wang ◽  
Zheng Yong Huang ◽  
Jian Li
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
High Speed ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Crystalline Phase Transition

Commercial poly (vinylidene fluoride) (PVDF) films are uniaxially stretched with varying rates at 110 °C in order to endow PVDF piezo-and pyroelectric by crystalline-phase transition from α to β during the stretching. The crystalline phases are determined by infrared spectroscopy. The β-phase content and its fraction in films increase as a result of stretching with high rates. In addition, higher stretching rates yield a slight increase of γ phase. The crystallite size is evaluated by means of X-ray diffraction. It is found that the β-phase crystallites become smaller with fast stretching, whereas the α-phase crystallites are cracked and disappear at high-speed stretching of 2.5 /min.

Photodegradation Studies of Poly(Vinylidene Fluoride)

2008 ◽  
Vol 587-588 ◽  
pp. 543-547 ◽  
Author(s):  
A.M. Gonçalves ◽  
Jivago Serrado-Nunes ◽  
Vitor Sencadas ◽  
Gabriela Botelho ◽  
Michael Belsley ◽  
...  
Keyword(s):  
Uv Radiation ◽  
High Stability ◽  
Vinylidene Fluoride ◽  
Piezoelectric Response ◽  
Xenon Lamp ◽  
Chemical Structures ◽  
Β Phase ◽  
Before And After ◽  
Poly Vinylidene Fluoride

In this work, commercial poly(vinylidene fluoride) PVDF, in its β phase was analysed before and after the samples were exposed to UV radiation using a xenon lamp, for ten weeks. Changes in chemical structures, crystallinity, dielectric and piezoelectric response were investigated. From the present study it can be concluded that PVDF shows high stability towards photodegradation and can be used for outdoor applications without interference in its performance.

Potential of Polarized PVDF/Carbon Nanotube Nanocomposite Scaffolds for Cell Growth

2015 ◽  
Vol 1718 ◽  
pp. 15-20
Author(s):  
Jun Young Lim ◽  
Sook Young Park ◽  
Hyun Jeong Kim ◽  
Yongsok Seo
Keyword(s):  
Carbon Nanotube ◽  
Vinylidene Fluoride ◽  
Electrospinning Process ◽  
Piezoelectric Response ◽  
Pvdf Film ◽  
Multiwalled Carbon ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Diphenyl Tetrazolium Bromide ◽  
Nanocomposite Scaffolds

ABSTRACTWe investigated the effects of varying the multiwalled carbon nanotube (MWCNT) contents, as well as the additional use of drawing and poling on the polymorphic behavior and electroactive (piezoelectric) properties of the cast poly(vinylidene fluoride) (PVDF)/MWCNT membranes. Dramatic changes occurred in the polar β-phase crystal contents with the MWCNT loading. An optimum concentration of MWCNT exists for PVDF film polarization. On the other hand, films prepared by electrospinning process exhibited almost constant amount of β-phase with the MWCNT concentration. In this process, polymer fibers with diameters down to the nanometer range, or nanofibers, are formed by subjecting a fluid jet to a high electric field. The remanent polarization and piezoelectric response increased with the β-phase crystals. Cell adhesion and proliferation measured with MTT (Methylthiazolyl diphenyl-tetrazolium bromide) assay coincidentally responded to the polarized PVDF films (β-phase amount).

Probing the synergism of halloysite nanotubes and electrospinning on crystallinity, polymorphism and piezoelectric performance of poly(vinylidene fluoride)

RSC Advances ◽  
2016 ◽  
Vol 6 (115) ◽  
pp. 114052-114060 ◽  
Author(s):  
Mohammed Khalifa ◽  
Arunjunairaj Mahendran ◽  
S. Anandhan
Keyword(s):  
Vinylidene Fluoride ◽  
Halloysite Nanotubes ◽  
Piezoelectric Response ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Piezoelectric Performance

Halloysite nanotubes (HNT) and electrospinning synergistically promoted the formation of β-phase in poly(vinylidene fluoride) (PVDF) from which a maximum piezoelectric response of 955 mV was obtained under a load of 100 g.

scholarly journals ARATION AND CHARACTERIZATION POLY (VINYLIDENE FLUORIDE-TRIFLUOROETHYLENE) COPOLYMER THIN FILMS FOR ORGANIC FERROELECTRIC FIELD EFFECT THIN FILM TRANSISTORS.

2015 ◽  
Vol 2 (1) ◽  
pp. 7-10
Author(s):  
Chandar Shekar B ◽  
Sulana Sundari ◽  
Sunnitha S ◽  
Sharmila C
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Layer ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Piezoelectric Response ◽  
Amorphous Nature ◽  
Poly Vinylidene Fluoride

Polyvinylidene fluoride (PVDF) and Trifluoroethylene ((TrFE) are potential polymers which are used in acoustic transducers and electromechanical actuators because of their inherent piezoelectric response, as heat sensors because of their inherent pyroelectric response and as dielectric layer in organic thin filmtransistors. In the present study thin films of copolymer Poly(vinylidene fluoride-trifluoroethylene) were prepared by spin coating method for two different concentrations 2% to 8% and for various spin speeds from 2000 RPM to 5000 RPM. A P-type Si wafer was used as a substrate to deposit P(VDF-TrFE) thin films. 2-butanone was used as a solvent to prepare P(VDF-TrFE) solution. To study the annealing effect, the films were annealed for three different temperatures 50°C, 100° C and 175° C. Ellipsometry was used to measure the thickness of the films. The identification of the films prepared was done by using FTIR spectrophotometer. The structure of the films was studied by using small angle XRD. The morphology of the coated surface was investigated using SEM. It is observed that the thickness of the film coated depends on concentration, spin speed and annealing temperature. The XRD spectrum indicated the amorphous nature with crystallites of very low dimension. SEM micrographs also conforms the predominantly amorphous nature of the film surface. The observed smooth surface with amorphous structure indicated that these films could be used as dielectric layer in organic ferroelectric field effect thin film transistors.

scholarly journals Development of poly (vinylidene fluoride)/silver nanoparticle electrospun nanofibre mats for energy harvesting

2021 ◽  
pp. 096739112110420
Author(s):  
Roopa Thotadara Shivalingappa ◽  
Hebbale Narayana Rao Narasimha Murthy ◽  
Pradeep Purushothaman ◽  
Prasanna Badiger ◽  
Swapnil Savarn ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Piezoelectric Materials ◽  
Applied Pressure ◽  
Fibre Diameter ◽  
X Ray Diffraction ◽  
Β Phase ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Poly Vinylidene Fluoride

Energy harvesting using piezoelectric materials finds attention of researchers due to miniaturisation. Polyvinylidene fluoride (PVDF) is one such polymeric material with high piezoelectric and pyroelectric properties and hence is used for sensors, actuators, energy harvesting and biomedical devices. This study reports electrospinning of PVDF/Ag nanoparticles (AgNP) nanofibre mats for energy harvesting. Nanofibre mats were prepared by adopting voltage (20 kV), flow rate (1.5 mL/hour) and tip to collector distance (19 cm). The fibre mats were characterised using Fourier-Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). FTIR and XRD results showed 11.84% and 36.36% increase in β-phase and crystallinity, respectively, due to the addition of 1.5 wt. % AgNP to PVDF. SEM micrographs showed decrease in bead formation and increase in fibre diameter from 40 nm to 355 nm due to the addition of AgNP. Sensitivity and voltage output were studied. The fibre mats were used for development of a miniature burglar alarm system, and its response to the applied pressure was tested.

Comparative study on the dielectric properties of three polyvinylidene fluoride nanocomposites incorporated with carbon filler

2017 ◽  
Vol 31 (8) ◽  
pp. 1102-1111 ◽  
Author(s):  
Dandan Yang ◽  
Haiping Xu ◽  
Wei Yu
Keyword(s):  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Hot Press ◽  
X Ray Diffraction ◽  
Carbon Filler ◽  
Solution Blending ◽  
Β Phase ◽  
Pristine Cnts ◽  
Poly Vinylidene Fluoride ◽  
Press Method

Poly(vinylidene fluoride) (PVDF)-carbon nanotube (CNT) composites with three different CNTs were prepared by a solution blending and hot-press method. The morphologies of nanocomposites were studied by scanning electron microscopy. The X-ray diffraction and differential scanning calorimeter data indicated that the addition of CNTs can promote the formation of β-phase of PVDF. The dielectric constant values of three PVDF/CNTs are much greater than that of neat PVDF. It has been found that the dielectric loss of the short hydroxylated CNTs filled PVDF nanocomposite is lower than those of other two long pristine CNTs filled PVDF nanocomposites.

High Efficient and Continuous Triboelectric Power Harvesting based on Porous β-phase Poly (vinylidene fluoride) Aerogel

2021 ◽  
Author(s):  
Minmin Wang ◽  
Weiqun Liu ◽  
Xu Shi ◽  
Jinyang Pan ◽  
Bing Zhou ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
High Electron ◽  
Exchange Method ◽  
Power Harvesting ◽  
Β Phase ◽  
Output Performance ◽  
High Electron Affinity ◽  
High Efficient ◽  
Poly Vinylidene Fluoride ◽  
High Output

Non-additive β-phase porous poly (vinylidene fluoride) (PVDF) aerogel with high electron affinity is successfully prepared through simple solvent exchange method. The as-prepared additive-free PVDF aerogel shows high output performance used...

scholarly journals Comparative Study of PVDF Sheets and Their Sensitivity to Mechanical Vibrations: The Role of Dimensions, Molecular Weight, Stretching and Poling

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1637
Author(s):  
Miroslav Mrlík ◽  
Josef Osička ◽  
Martin Cvek ◽  
Markéta Ilčíková ◽  
Peter Srnec ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Comparative Study ◽  
Vinylidene Fluoride ◽  
Initial Thickness ◽  
Complementary Method ◽  
Β Phase ◽  
Vibration Sensing ◽  
Poly Vinylidene Fluoride ◽  
Processing Techniques ◽  
The Comparative Study

This paper is focused on the comparative study of the vibration sensing capabilities of poly(vinylidene fluoride) (PVDF) sheets. The main parameters such as molecular weight, initial sample thickness, stretching and poling were systematically applied, and their impact on sensing behavior was examined. The mechanical properties of prepared sheets were investigated via tensile testing on the samples with various initial thicknesses. The transformation of the α-phase to the electro-active β-phase was analyzed using FTIR after applying stretching and poling procedures as crucial post-processing techniques. As a complementary method, the XRD was applied, and it confirmed the crystallinity data resulting from the FTIR analysis. The highest degree of phase transformation was found in the PVDF sheet with a moderate molecular weight (Mw of 275 kDa) after being subjected to the highest axial elongation (500%); in this case, the β-phase content reached approximately 90%. Finally, the vibration sensing capability was systematically determined, and all the mentioned processing/molecular parameters were taken into consideration. The whole range of the elongations (from 50 to 500%) applied on the PVDF sheets with an Mw of 180 and 275 kDa and an initial thickness of 0.5 mm appeared to be sufficient for vibration sensing purposes, showing a d33 piezoelectric charge coefficient from 7 pC N−1 to 9.9 pC N−1. In terms of the d33, the PVDF sheets were suitable regardless of their Mw only after applying the elongation of 500%. Among all the investigated samples, those with an initial thickness of 1.0 mm did not seem to be suitable for vibration sensing purposes.

scholarly journals Studies on the electrostatic effects of stretched PVDF films and nanofibers

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yixuan Lin ◽  
Yuqiong Zhang ◽  
Fan Zhang ◽  
Meining Zhang ◽  
Dalong Li ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Polarized Light ◽  
Transition Process ◽  
Open Circuit ◽  
Wearable Electronics ◽  
Energy Harvesters ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Piezoelectric Effects ◽  
Energy Harvesting Devices

AbstractThe electroactive β-phase in Poly (vinylidene fluoride, PVDF) is the most desirable conformation due to its highest pyro- and piezoelectric properties, which make it feasible to be used as flexible sensors, wearable electronics, and energy harvesters etc. In this study, we successfully developed a method to obtain high-content β-phase PVDF films and nanofiber meshes by mechanical stretching and electric spinning. The phase transition process and pyro- and piezoelectric effects of stretched films and nanofiber meshes were characterized by monitoring the polarized light microscopy (PLM) images, outputting currents and open-circuit voltages respectively, which were proved to be closely related to stretching ratio (λ) and concentrations. This study could expand a new route for the easy fabrication and wide application of PVDF films or fibers in wearable electronics, sensors, and energy harvesting devices.

Sign in / Sign up

Export Citation Format

Share Document