scholarly journals Facile preparation of highly oriented poly(vinylidene fluoride) uniform films and their ferro- and piezoelectric properties

RSC Advances ◽  
2017 ◽  
Vol 7 (28) ◽  
pp. 17038-17043 ◽  
Author(s):  
Fan Xu ◽  
Kaili Zhang ◽  
Ying Zhou ◽  
Zhichao Qu ◽  
Haijun Wang ◽  
...  

The shear-induced PVDF films present preferentially orientation with a high β-phase content and exhibit excellent ferro- and piezoelectric properties.

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3292
Author(s):  
Wu Guo ◽  
Zhaogang Liu ◽  
Yan Zhu ◽  
Li Li

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.


2020 ◽  
Vol 44 (34) ◽  
pp. 14578-14591
Author(s):  
Akash M. Chandran ◽  
S. Varun ◽  
Prasanna Kumar S. Mural

In the present study, we report a simple fabrication method for poly(vinylidene fluoride) PVDF/MWCNT flexible nanocomposite films with a boosted electroactive phase that enhanced the dielectric and piezoelectric properties.


Polimery ◽  
2021 ◽  
Vol 66 (10) ◽  
pp. 532
Author(s):  
Aminatul Sobirah Zahari ◽  
Muhammad Hafiz Mazwir ◽  
Izan Izwan Misnon

A significant influence of the molecular weight on the dielectric properties and piezoelectric constant of poly(vinylidene fluoride) (PVDF) membranes obtained by electrospinning was demonstrated. Electrochemical impedance spectroscopy and d33 meter were used to evaluate dielectric properties and piezoelectric constant respectively. The presence of the β-phase was determined by Fourier transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD). The membranes with the lowest molecular weight (180,000 g/mol) possessed the best dielectric properties. They also had the highest piezoelectric constant (21 pC/N) and dielectric constant (2.9 at 50 Hz) as well as the highest β-phase content (80.25%).


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Nan Meng ◽  
Xintong Ren ◽  
Giovanni Santagiuliana ◽  
Leonardo Ventura ◽  
Han Zhang ◽  
...  

Abstract Poly(vinylidene fluoride)-based dielectric materials are prospective candidates for high power density electric storage applications because of their ferroelectric nature, high dielectric breakdown strength and superior processability. However, obtaining a polar phase with relaxor-like behavior in poly(vinylidene fluoride), as required for high energy storage density, is a major challenge. To date, this has been achieved using complex and expensive synthesis of copolymers and terpolymers or via irradiation with high-energy electron-beam or γ-ray radiations. Herein, a facile process of pressing-and-folding is proposed to produce β-poly(vinylidene fluoride) (β-phase content: ~98%) with relaxor-like behavior observed in poly(vinylidene fluoride) with high molecular weight > 534 kg mol−1, without the need of any hazardous gases, solvents, electrical or chemical treatments. An ultra-high energy density (35 J cm−3) with a high efficiency (74%) is achieved in a pressed-and-folded poly(vinylidene fluoride) (670-700 kg mol−1), which is higher than that of other reported polymer-based dielectric capacitors to the best of our knowledge.


2021 ◽  
Author(s):  
Minmin Wang ◽  
Weiqun Liu ◽  
Xu Shi ◽  
Jinyang Pan ◽  
Bing Zhou ◽  
...  

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...


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