scholarly journals Characterization and Application of PVDF and Its Copolymer Films Prepared by Spin-Coating and Langmuir–Blodgett Method

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2033 ◽  
Author(s):  
Zerun Yin ◽  
Bobo Tian ◽  
Qiuxiang Zhu ◽  
Chungang Duan
Keyword(s):  
Spin Coating ◽  
Vinylidene Fluoride ◽  
Medical Applications ◽  
Ongoing Research ◽  
Langmuir Blodgett ◽  
Copolymer Films ◽  
The Past ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Ε Phase

Poly(vinylidene fluoride) (PVDF) and its copolymers are key polymers, displaying properties such as flexibility and electroactive responses, including piezoelectricity, pyroelectricity, and ferroelectricity. In the past several years, they have been applied in numerous applications, such as memory, transducers, actuators, and energy harvesting and have shown thriving prospects in the ongoing research and commercialization process. The crystalline polymorphs of PVDF can present nonpolar α, ε phase and polar β, γ, and δ phases with different processing methods. The copolymers, such as poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), can crystallize directly into a phase analogous to the β phase of PVDF. Since the β phase shows the highest dipole moment among polar phases, many reproducible and efficient methods producing β-phase PVDF and its copolymer have been proposed. In this review, PVDF and its copolymer films prepared by spin-coating and Langmuir–Blodgett (LB) method are introduced, and relevant characterization techniques are highlighted. Finally, the development of memory, artificial synapses, and medical applications based on PVDF and its copolymers is elaborated.

scholarly journals Development of In-Situ Poled Nanofiber Based Flexible Piezoelectric Nanogenerators for Self-Powered Motion Monitoring

2020 ◽  
Vol 10 (10) ◽  
pp. 3493
Author(s):  
Minjung Kim ◽  
Vignesh Krishnamoorthi Kaliannagounder ◽  
Afeesh Rajan Unnithan ◽  
Chan Hee Park ◽  
Cheol Sang Kim ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Implantable Devices ◽  
The Past ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
High Bias ◽  
Self Powered ◽  
Increasing Demand ◽  
Piezoelectric Nanogenerators

Energy harvesting technologies have found significant importance over the past decades due to the increasing demand of energy and self-powered design of electronic and implantable devices. Herein, we demonstrate the design and application of in situ poled highly flexible piezoelectric poly vinylidene fluoride (PVDF) graphene oxide (GO) hybrid nanofibers in aligned mode for multifaceted applications from locomotion sensors to self-powered motion monitoring. Here we exploited the simplest and most versatile method, called electrospinning, to fabricate the in situ poled nanofibers by transforming non-polar α-phase of PVDF to polar β- phase structures for enhanced piezoelectricity under high bias voltage. The flexible piezoelectric device fabricated using the aligned mode generates an improved output voltage of 2.1 V at a uniform force of 12 N. The effective piezoelectric transduction exhibited by the proposed system was tested for its multiple efficacies as a locomotion detector, bio-e-skin, smart chairs and so on.

scholarly journals Phase Inversion in PVDF Films with Enhanced Piezoresponse Through Spin-Coating and Quenching

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1096 ◽  
Author(s):  
Fortunato ◽  
Cavallini ◽  
De Bellis ◽  
Marra ◽  
Tamburrano ◽  
...  
Keyword(s):  
Spin Coating ◽  
Phase Inversion ◽  
Vinylidene Fluoride ◽  
Wearable Sensors ◽  
Polymer Concentration ◽  
Low Viscosity ◽  
Β Phase ◽  
Best Value ◽  
Poly Vinylidene Fluoride ◽  
Mechanical Stretching

In the present work, poly(vinylidene fluoride) (PVDF) films were produced by spin-coating, and applying different conditions of quenching, in order to investigate the dominant mechanism of the β-phase formation. The influence of the polymer/solvent mass ratio of the solution, the rotational speed of the spin-coater and the crystallization temperature of the film on both the β-phase content and the piezoelectric coefficient (d33) were investigated. This study demonstrates that the highest values of d33 are obtained when thinner films, produced with a lower concentration of polymer in the solvent (i.e., 20 wt.%), go through quenching in water, at room temperature. Whereas, in the case of higher polymer concentration (i.e., 30 wt.%), the best value of d33 (~30 pm/V) was obtained through quenching in liquid nitrogen, at the temperature of 77 K. We believe that in the former case, phase inversion is mainly originated by electrostatic interaction of PVDF with the polar molecules of water, due to the low viscosity of the polymer solution. On the contrary, in the latter case, due to higher viscosity of the solution, mechanical stretching induced on the polymer during spin-coating deposition is the main factor inducing self-alignment of the β-phase. These findings open up a new way to realize highly efficient devices for energy harvesting and wearable sensors.

Ferroelectricity of poly(vinylidene fluoride) homopolymer Langmuir–Blodgett nanofilms

2014 ◽  
Vol 2 (33) ◽  
pp. 6727-6731 ◽  
Author(s):  
Huie Zhu ◽  
Shunsuke Yamamoto ◽  
Jun Matsui ◽  
Tokuji Miyashita ◽  
Masaya Mitsuishi
Keyword(s):  
Remanent Polarization ◽  
Vinylidene Fluoride ◽  
Langmuir Blodgett ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Fatigue Endurance

As-deposited PVDF LB nanofilms with a complete β phase show a remarkable remanent polarization and long fatigue endurance greater than 105cycles.

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.

Understanding nucleation of the electroactive β-phase of poly(vinylidene fluoride) by nanostructures

RSC Advances ◽  
2016 ◽  
Vol 6 (114) ◽  
pp. 113007-113015 ◽  
Author(s):  
M. S. Sebastian ◽  
A. Larrea ◽  
R. Gonçalves ◽  
T. Alejo ◽  
J. L. Vilas ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Β Phase ◽  
Poly Vinylidene Fluoride

scholarly journals Fabrication of Poly(Vinylidene Fluoride)/Graphene Nano-Composite Micro-Parts with Increased β-Phase and Enhanced Toughness via Micro-Injection Molding

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3292
Author(s):  
Wu Guo ◽  
Zhaogang Liu ◽  
Yan Zhu ◽  
Li Li
Keyword(s):  
Injection Molding ◽  
Vinylidene Fluoride ◽  
Structure Evolution ◽  
Phase Content ◽  
Micro Injection Molding ◽  
Nano Composite ◽  
Injection Speed ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Micro Parts

Based on poly(vinylidene fluoride)/graphene (PVDF/GP) nano-composite powder, with high β-phase content (>90%), prepared on our self-designed pan-mill mechanochemical reactor, the micro-injection molding of PVDF/GP composite was successfully realized and micro-parts with good replication and dimensional stability were achieved. The filling behaviors and the structure evolution of the composite during the extremely narrow channel of the micro-injection molding were systematically studied. In contrast to conventional injection molding, the extremely high injection speed and small cavity of micro-injection molding produced a high shear force and cooling rate, leading to the obvious “skin-core” structure of the micro-parts and the orientation of both PVDF and GP in the shear layer, thus, endowing the micro-parts with a higher melting point and crystallinity and also inducing the transformation of more α-phase PVDF to β-phase. At the injection speed of 500 mm/s, the β-phase PVDF in the micro-part was 78%, almost two times of that in the macro-part, which was beneficial to improve the dielectric properties. The micro-part had the higher tensile strength (57.6 MPa) and elongation at break (53.6%) than those of the macro-part, due to its increased crystallinity and β-phase content.

Sign in / Sign up

Export Citation Format

Share Document