Microstructure and ferroelectrical properties of the copolymers of vinylidene fluoride with tetrafluoroethylene of composition 71:29

Kochervinskiĭ, V. V.; Murasheva, Ye.M.

doi:10.1016/0032-3950(91)90095-8

Cited by 7 publications

(13 citation statements)

References 9 publications

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“…According to NMR, the lowest concentration of head-to-head (HHTT) defects was detected in VDF/TFE 71/29 copolymer. 15,16 This fact can serve as an additional factor that promotes the increase in both the longitudinal crystal size and the length of regular sequences of rotational isomers.…”

Section: Discussionmentioning

confidence: 99%

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Influence of parameters of molecular mobility on formation of structure in ferroelectric vinylidene fluoride copolymers

Kochervinskiĭ

Malyshkina

Павлов

et al. 2015

Journal of Applied Physics

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Articles you may be interested inStructural and dielectric properties of poly(vinylidene fluoride)-based terpolymer/copolymer blends developed on aluminum foil J. Appl. Phys. 112, 053505 (2012); 10.1063/1.4748181 Interacting and noninteracting dipole systems in ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer J. Appl. Phys. 108, 084109 (2010); 10.1063/1.3499614 Structural evolution and dielectric relaxation behavior of electron-irradiated poly(vinylidene fluoride-trifluoroethylene) 80/20 mol % copolymers J. Appl. Phys. 94, 5566 (2003); 10.1063/1.1606853 Infrared spectroscopic ellipsometry study of vinylidene fluoride (70%)-trifluoroethylene (30%) copolymer Langmuir-Blodgett films J. Appl. Phys. 94, 195 (2003); 10.1063/1.1578697Dielectric relaxation behavior and its relation to microstructure in relaxor ferroelectric polymers: High-energy electron irradiated poly(vinylidene fluoride-trifluoroethylene) copolymersThe low-temperature molecular mobility has been studied by dielectric relaxation spectroscopy on the bulk films of statistic copolymers of vinylidene fluoride (VDF) with tetra-(TFE) and trifluoroethylene obtained by crystallization from a solution in acetone. The results show that activation energy of the kinetic units in the glassy state depends significantly on the concentration of polar groups. The cooperative mobility above the glass transition temperature is described by Vogel-Tamman-Fulcher equation; the lowest value of the effective activation energy was found in the copolymer with highest amount of non-polar TFE content. It has been shown that the parameters of the dynamics are related to the structural parameters obtained by infrared spectroscopy, wide-angle X-ray Spectroscopy, and small-angle X-ray scattering. In particular, the largest crystals and the highest value of the "large" period have been detected in VDF/TFE copolymer with lowest activation parameters of microbrownian and local mobility. Number of lamellar crystals in stacks is determined by the concentration of VDF polar groups in copolymer chain. V C 2015 AIP Publishing LLC.

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Section: Discussionmentioning

confidence: 99%

“…Their chain microstructure was previously characterized by high resolution NMR. 15,16 The polymer films of VDF/TFE and VDF/TrFE 70/30 copolymers were prepared by crystallization from a solution in acetone. 8 wt.…”

Section: Experimental Partmentioning

confidence: 99%

Influence of parameters of molecular mobility on formation of structure in ferroelectric vinylidene fluoride copolymers

Kochervinskiĭ

Malyshkina

Павлов

et al. 2015

Journal of Applied Physics

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“…Samples of a VDF-TFE copolymer with a molar composition of 94:6 (sample #1) and 71:29 (sample #2) were studied; the microstructure of the copolymer was previously characterized via a 19 F NMR technique [11,12]. The fraction of head-tohead (HHTT) chemical defects in the studied copolymer #1 is 4.2 mol%.…”

Section: Samples and Experimental Techniquesmentioning

confidence: 99%

“…2). It should be remembered, however, that copolymer #2 is characterized by lower coercive fields than copolymer #1 [11,12]. This fact should also be considered when analyzing the field dependence of highvoltage conductivity.…”

Section: Samples and Experimental Techniquesmentioning

confidence: 99%

Local piezoelectric response, structural and dynamic properties of ferroelectric copolymers of vinylidene fluoride–tetrafluoroethylene

et al. 2014

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The characteristics of the local piezoelectric response of isotropic films of copolymers of vinylidene fluoride (VDF) were compared with 6 and 29 mol% tetrafluoroethylene (TFE) obtained by crystallization from a solution in acetone. Time dependence of the electric displacement response was analyzed after switching of the spontaneous polarization. A copolymer with a higher content of tetrafluoroethylene is characterized by higher values of electrical displacement and piezoelectric response. For interpretation of this fact, we used molecular mobility in amorphous phase dates. It is shown that the activation energy of local and cooperative liquid-like (in the amorphous phase) mobility is markedly lower in the copolymer with a higher content of TFE. Under identical conditions of the crystallization, both films of the copolymers lead to the formation of larger crystals of the polar phase and magnitude of a "long" period at a high content of copolymer of TFE. It is postulated that these structural parameters are responsible for the stable value of residual local piezoelectric activity. It is found that the rapid decay of the signal in the local piezoresponse of polarized films is controlled by the activation energy of the local and cooperative dynamics chains of the amorphous phase.

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“…Later, some related researches concerned the differences of ferroelectric P(VDF‐TrFE) and P(VDF‐TFE) in conformation of molecular chains for expressing their electric properties . P(VDF‐TFE) also has the spontaneous β form since the TFE monomer somewhat has the same effect as the head‐to‐head sequences (CF 2 CH 2 CH 2 CF 2 ) of PVDF, and all‐ trans P(VDF‐TFE) exhibits good piezo‐ and ferroelectric properties as well.…”

Section: Introductionmentioning

confidence: 99%

Influence of Steric Hindrance on Ferro‐ and Piezoelectric Performance of Poly(vinylidene fluoride)‐Based Ferroelectric Polymers

Liao

et al. 2019

Macro Chemistry & Physics

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Poly(vinylidene fluoride) (PVDF) and copolymers possess excellent ferro‐ and piezoelectric properties, and highly expected to be utilized as sensors in the areas covering the smart wearer, hydrophone, speaker, and medical ultrasonic devices. Besides PVDF in β crystalline phase, the copolymers with trifluoroethylene (TrFE) and tetrafluoroethylene (TFE) are widely investigated both in academia and industry. To illustrate how the steric hindrance between VDF and TrFE/TFE affects the condensed‐state structure and electric properties of the polymers, the electric properties and their dependences on molecular configuration and crystal structures of PVDF, P(VDF‐TrFE), and P(VDF‐TFE) are comparatively investigated. The introduction of same molar contents (20 mol%) of TrFE and TFE monomers into PVDF chain leads to the similar conformation transformation from α (γ ) phase to β phase and similar crystallinity in resultant P(VDF‐TFE) and P(VDF‐TrFE) thanks to the depressed energy of trans conformation and the increased energy barrier between anti‐gauche and trans conformation. That leads to the more preferred β‐phase and ferroelectric domains generated in P(VDF‐TrFE) and P(VDF‐TFE). Both the size of ferroelectric phase, the polarity of the polymer chain, the organization and orientation of the grains along the field are responsible for the excellent piezoelectric field resulted by the varied composition as well.

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Microstructure and ferroelectrical properties of the copolymers of vinylidene fluoride with tetrafluoroethylene of composition 71:29

Cited by 7 publications

References 9 publications

Influence of parameters of molecular mobility on formation of structure in ferroelectric vinylidene fluoride copolymers

Influence of parameters of molecular mobility on formation of structure in ferroelectric vinylidene fluoride copolymers

Local piezoelectric response, structural and dynamic properties of ferroelectric copolymers of vinylidene fluoride–tetrafluoroethylene

Influence of Steric Hindrance on Ferro‐ and Piezoelectric Performance of Poly(vinylidene fluoride)‐Based Ferroelectric Polymers

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