Piezoelectricity of vinylidene fluoride-trifluoroethylene copolymers

Higashihata, Yoshihide; Sako, Junichi; Yagi, Toshiharu

doi:10.1080/00150198108238678

Cited by 166 publications

(66 citation statements)

References 10 publications

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“…The temperature of this peak is consistent with that of the anomalous peak T :U in dielectric and piezoelectric constants observed by Higashihata et a/. 8 Thus, the T, dispersion may be due to the ferroelectric to paraelectric phase transition. Yagi eta!.…”

Section: Resultssupporting

confidence: 75%

“…Higashihata et a/. 8 observed that the dielectric and piezoelectric constants for these copolymers showed anomalous peaks above room temperature, the size of which was maximum at an intermediate content of the comonomer and that the peak temperature of these constants agreed with the phase transition temperature for copolymers with 18 to 51 mol% TrFE. For copolymers with TrFE content of 63 and 87 mol%, the phase transition was observed around 318 K in X-ray measurements, being ascribed to the ferroelectric to paraelectric phase transition.…”

mentioning

confidence: 73%

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Dynamic Mechanical Dispersion in Copolymers of Vinylidene Fluoride and Trifluoroethylene

Murata

Koizumi

1985

Polym J

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ABSTRACT:Copolymers of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) with TrFE content ranging from 48 to lOOmol% were studied by dynamic mechanical measurements in a temperature range of 173 to 373 Kat 3.5 Hz. The IX and f3 dispersions were observed around 313 and 250 K in decreasing order of temperature and the T, dispersion occurred at higher temperature above the IX dispersion for copolymers with 48 to 71 mol% TrFE. It was inferred for copolymers with 48 to 71 mol% TrFE from the dependence of these dispersions on degree of crystallinity that the IX and f3 dispersions were due to micro-Brownian molecular motions ofTrFE rich and VDF rich sequences respectively in amorphous regions and that the T, dispersion was connected to the phase transition in crystalline regions. It was noted that the f3 dispersion in copolymer with higher TrFE content was related to the local molecular motions in amorphous and crystalline regions.KEY WORDS

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Section: Resultssupporting

confidence: 75%

mentioning

confidence: 73%

Dynamic Mechanical Dispersion in Copolymers of Vinylidene Fluoride and Trifluoroethylene

Murata

Koizumi

1985

Polym J

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“…The absorption peaks at 840, 880, 1273, and 1396 cm −1 correspond to the ferroelectric crystal phase Form I of P(VDF-TrFE). 23,35) In contrast, characteristic peaks for paraelectric Form II (α) of P(VDFTrFE) are hardly observed. Therefore, the P(VDF-TrFE) molecules in the gel state predominantly exhibit ferroelectric crystal phase Form I.…”

Section: Resultsmentioning

confidence: 98%

“…[15][16][17][18][19][20][21][22][23] Ferroelectric Form I (β phase), with an all-trans configuration in P(VDF-TrFE), exhibits the best ferroelectric and piezoelectric properties. A sandwich device prepared using solidstate P(VDF-TrFE) films exhibited both direct and inverse piezoelectric effects.…”

Section: Introductionmentioning

confidence: 99%

Anomalous piezoelectric properties of poly(vinylidene fluoride–trifluoroethylene)/ionic liquid gels

Fukagawa

Koshiba

Fukushima

et al. 2018

Jpn. J. Appl. Phys.

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Piezoelectric gels were prepared from low-volatile ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) gels, and their structural, ferroelectric, and piezoelectric properties were investigated. Poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE)/IL gels were formed using thermally reversible physical gels. The structural characterization indicated that the P(VDF-TrFE) molecules in the gels predominantly formed a ferroelectric phase (Form I) of P(VDF-TrFE). Polarization switching peaks were clearly observed using a three-layer stacked device structure. The coercive field of the P(VDF-TrFE)/IL gels substantially decreased to 4-9 MV/m, and their remnant polarizations were maintained at 63-71 mC/m 2 , which is similar to that for typical solid-state P(VDF-TrFE). Finally, the P(VDF-TrFE)/IL gel films exhibited a piezoelectric response, and the highest piezoelectric coefficient was >300 pm/V at an applied voltage frequency of 4 kHz.

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“…10 The s' peak was observed at 333 to 338 K also for copolymers with 48 to 87 mo!% Tr FE as shown in the previous paper.11· 25 The reciprocal of s' is plotted against temperature for 48 to 87 mo!% TrFE copolymers in Figure 15 were 1/s' decreases and increases almost linearly with increasing temperature for 48 to 87mol% TrFE Table II. The values of C 1 and C 2 for these samples were larger than those for copolymer with 48 mo!% TrFE.…”

Section: High Temperature Transitionmentioning

confidence: 83%

Relaxation and Transition of Copolymers of Vinylidene Fluoride and Trifluoroethylene with High Trifluoroethylene Content

Murata

1988

Polym J

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ABSTRACT:Dielectric behavior and related properties were investigated for copolymers of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) with TrFE content from 35 to 87mol%.Three dielectric loss peaks, designated as /3', {3, and T, were observed in increasing order of temperature. The {3' relaxation was predominant in samples with high crystallinity for all copolymers and was connected with molecular motion around defects due to anomalous linkages of head-to-head and tail-to-tail of TrFE rich sequences. The f3 relaxation found in samples with low crystallinity was related to micro-Brownian motion of VDF rich sequences in main chains for 35 to 67mol% TrFE copolymers. In copolymers with 71 and 87mol% TrFE, the f3 relaxation was considered to consist of two components, fJ. and /Jc, due to the local molecular motions in amorphous and crystalline regions, respectively. The T, loss peak was related to a transition between the phase of antiferroelectric nature and paraelectric phase for 48 to 87mol% TrFE copolymers. The transition for 63 and 71 mo!% Tr FE copolymers exhibited characters of the first or second order of the transition, depending on the physical properties observed. Pressure dependence of the T, transition temperature was smaller for 63 and 71 mo!% TrFE copolymers than that for 48 and 35mol% TrFE copolymers.KEY WORDS Vinylidene Fluoride-Trifluoroethylene Copolymer / High Trifluoroethylene Content/ Dielectric Relaxation/ Defect/ Head-to-Head/ Tail-to-Tail / Phase Transition / The relaxation behavior of copolymers of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) with high TrFE content was studied by dynamic mechanical measurements. IX and {3 relaxations due to micro-Brownian motion ofTrFE and VDF rich sequences were found at 313 and 250 K, respectively, for copolymers with 48 to 71 mol% TrFE. 1 Yagi also found two relaxations connected with micro-Brownian motion for copolymers with 40 to 63 mol% Tr FE in dynamic mechanical study. 2 Furukawa et al. 3 studied dielectric behavior of VDF-TrFE copolymers with the entire range of comonomer content and found a relaxation at 253 K at 1 kHz. The relaxation at 253 K was ascribed to the same type of molecular motion in the amorphous region as that of the transformation of trans and gauche at the ferroelectric to paraelectric transition. Koizumi et al. 4 found {3 relaxation due to micro-Brownian motion around 250 K and y relaxation connected with local molecular motion in frozen glassy state at lower temperature. Different relaxation mechanisms were presented for relaxation around 253 K by these authors. For polytrifluoroethylene (PTrFE) two types of relaxation in the crystalline region were found below room temperature and considered to be due to reorientation of main chains around row vacancy defects at chain ends and molecular motion of disordered chains around anomalous linkages such as 771

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Piezoelectricity of vinylidene fluoride-trifluoroethylene copolymers

Cited by 166 publications

References 10 publications

Dynamic Mechanical Dispersion in Copolymers of Vinylidene Fluoride and Trifluoroethylene

Dynamic Mechanical Dispersion in Copolymers of Vinylidene Fluoride and Trifluoroethylene

Anomalous piezoelectric properties of poly(vinylidene fluoride–trifluoroethylene)/ionic liquid gels

Relaxation and Transition of Copolymers of Vinylidene Fluoride and Trifluoroethylene with High Trifluoroethylene Content

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