Novel Continuous Poly(vinylidene fluoride) Nanofibers

2006 ◽  
Vol 920 ◽  
Author(s):  
Xi Ren ◽  
Yuris Dzenis
Keyword(s):  
Electric Fields ◽  
Vinylidene Fluoride ◽  
Ferroelectric Properties ◽  
Fiber Spinning ◽  
Raw Material ◽  
Synthetic Fiber ◽  
Fiber Properties ◽  
Electrospinning Method ◽  
Poly Vinylidene Fluoride ◽  
High Electric Fields

AbstractPoly(vinylidene fluoride) (PVDF) is well known for its ferroelectric and piezoelectric properties. Currently, this polymer is used in applications in the form of films. PVDF fibers are expected to open up exciting new opportunities such as design and use of active textiles and composites. It is well-known that synthetic fiber properties improve substantially with the decrease of their diameter. However, conventional mechanical fiber spinning processes usually produce fibers with diameters in the range from tens to hundreds of microns. In this work, ultrafine, submicron-diameter continuous PVDF nanofibers were fabricated by electrospinning method. The method consists of spinning polymer solutions in high electric fields. Effects of process parameters on nanofiber diameter and morphology were studied. XRD and FTIR analyses of PVDF nanofibers were performed. The latter indicated that the initial á phase of the raw material was converted to â phase PVDF during electrospinning. As â phase is primarily responsible for the piezo- and ferroelectric properties of PVDF, the latter result is very encouraging. The demonstrated novel continuous PVDF nanofibers can be used in nanostructured active textiles and composites and can lead to unusual new designs for actuators and sensors.

Polarization study of poly(vinylidene fluoride) films under cyclic electric fields

2020 ◽  
Vol 60 (3) ◽  
pp. 645-656
Author(s):  
Shuang Qin ◽  
Xu Zhang ◽  
Zheng Yu ◽  
Feng Zhao
Keyword(s):  
Electric Fields ◽  
Vinylidene Fluoride ◽  
Polarization Study ◽  
Poly Vinylidene Fluoride

Novel Polar-fluoropolymer Blends with Tailored Nanostructures for High Energy Density and Low Loss Capacitor Applications

2012 ◽  
Vol 1403 ◽  
Author(s):  
Shan Wu ◽  
Minren Lin ◽  
David S-G. Lu ◽  
Lei Zhu ◽  
Q. M. Zhang
Keyword(s):  
Dielectric Loss ◽  
Energy Density ◽  
Electric Fields ◽  
Vinylidene Fluoride ◽  
High Energy ◽  
High Energy Density ◽  
Low Loss ◽  
Blend Films ◽  
Low Dielectric ◽  
High Electric Fields

ABSTRACTDielectric polymers with high energy density with low loss at high electric fields are highly desired for many energy storage and regulation applications. A polar-fluoropolymer blend consisting of a high energy density polar-fluoropolymer of poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)) with a low dielectric loss polymer of poly(ethylene-chlorotrifluoroethylene) (ECTFE) was developed and investigated. We show that the two polymers are partially miscible which leads to blends with high energy density and low loss. Moreover, by introducing crosslinking to further tailor the nano-structures of the blends a markedly reduction of losses in the blend films at high field can be achieved. The crosslinked blend films show a dielectric constant of 7 with a dielectric loss of 1% at low field. Furthermore, the blends maintain a high energy density and low loss (∼3%) at high electric fields (> 250 MV/m).

scholarly journals Electrochromism of Viologen/Polymer Composite: From Gel to Insulating Bulk for High-Voltage Applications

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5901
Author(s):  
Yongjie Nie ◽  
Meng Zhang ◽  
Yuanwei Zhu ◽  
Yu Jing ◽  
Wenli Shi ◽  
...  
Keyword(s):  
Power Systems ◽  
Space Charge ◽  
Electric Fields ◽  
High Voltage ◽  
Vinylidene Fluoride ◽  
Power Equipment ◽  
Charge Accumulation ◽  
Charge Detection ◽  
Continuous Current ◽  
High Electric Fields

Power equipment operates under high voltages, inducing space charge accumulation on the surface of key insulating structures, which increases the risk of discharge/breakdown and the possibility of maintenance workers experiencing electric shock accidents. Hence, a visualized non-equipment space charge detection method is of great demand in the power industry. Typical electrochromic phenomenon is based on redox of the material, triggered by a voltage smaller than 5 V with a continuous current in μA~mA level, which is not applicable to high electric fields above 106 V/m with pA~nA operation current in power equipment. Until now, no naked-eye observation technique has been realized for space charge detection to ensure the operation of power systems as well as the safety of maintenance workers. In this work, a viologen/poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF–HFP)) composite is investigated from gel to insulating bulk configurations to achieve high-voltage electrical-insulating electrochromism. The results show that viologen/P(VDF–HFP) composite bulk can withstand high electric fields at the 107 V/m level, and its electrochromism is triggered by space charges. This electrochromism phenomenon can be visually extended by increasing viologen content towards 5 wt.% and shows a positive response to voltage amplitude and application duration. As viologen/P(VDF–HFP) composite bulk exhibits a typical electrical insulating performance, it could be attached to the surface of insulating structures or clamped between metal and insulating materials as a space charge accumulation indicator in high-voltage power equipment.

scholarly journals Enhancement of Piezoelectric Coefficient (d33) in PVDF-TrFe/CoFe2O4 nanocomposites through DC magnetic poling

2021 ◽  
Author(s):  
Marco Fortunato ◽  
Alessio Tamburrano ◽  
Maria Paola Bracciale ◽  
Maria Laura Santarelli ◽  
Maria Sabrina Sarto
Keyword(s):  
Magnetic Fields ◽  
Electric Fields ◽  
Piezoelectric Coefficient ◽  
Vinylidene Fluoride ◽  
Piezoelectric Materials ◽  
Low Cost ◽  
Sample Surface ◽  
Special Focus ◽  
Phase Alignment ◽  
Poly Vinylidene Fluoride

In the last years flexible, low-cost, wearable and innovative piezoelectric nanomaterials, have attracted a considerable interest to develop energy harvesters and sensors. Among the piezoelectric materials, a special focus was paid on  electroactive polymers such as Poly(vinylidene fluoride) [PVDF] and on its copolymer Poly(vinylidene fluoride-co-trifluoroethylene) [PVDF-TrFe], which is one of the most investigated piezoelectric polymers, due to the high β-phase content resulting under specific curing or processing conditions. However, to get high piezoelectric coefficient (d33), alignment of the β-phase domains is needed, which is usually obtained by applying a high electric fields at moderate temperatures. This process, usually referred as electrical poling, requires the deposition of contact electrodes over the sample surface, and the use of high voltage apparatus.   In the present work, in order to overcome these constraints we have produced, characterized and studied a polymer nanocomposite, consisting of CoFe2O4 nanoparticles dispersed in PVDF-TrFe with enhancement of the β-phase alignment through and applied a DC magnetic fields. The magnetic poling was demonstrated to be particular effective, leading to a piezoelectric coefficient, d33, with values up to 39 pm/V. The magnetic poling does not need the use a top electrode and of high magnetic fields (the maximum value of d33 was obtained at 50 mT, using a current of 0.4 A) making the PVDF-TrFE/CoFe2O4 nanocomposite suitable for the fabrication of highly efficient devices for energy harvesting and wearable sensors.

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