Dielectric relaxation spectra in ferroelectric P(VDF-TrFE) copolymers

Ménégotto, J.; Ibos, Laurent; Bernès, A.; Demont, Philippe; Lacabanne, C.

doi:10.1080/00150199908226122

Cited by 22 publications

(19 citation statements)

References 29 publications

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“…The second peak is bimodal (66.8 °C and 60.4 °C) and corresponds to the para‐to‐ferroelectric transition, with the formation of the perfect and defective ferroelectric phases. The large hysteresis of the Curie transition (about 50 °C) has been reported in many DSC studies and considered as an indicator of the ferroelectric‐to‐paralectric transition …”

Section: Resultsmentioning

confidence: 89%

Poling influence on the mechanical properties and molecular mobility of highly piezoelectric P(VDF‐TrFE) copolymer

Roggero

Dantras

Lacabanne

2017

J Polym Sci B Polym Phys

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The calorimetric, dielectric, and mechanical responses of highly piezoelectric 70/30 P(VDF‐TrFE) displaying homogenous d33 of −19 pC N−1 are studied. This work aims at better understanding the influence of poling on the mechanical properties of this copolymer. To explain the one decade mechanical modulus drop observed across the Curie transition, a stiffening process of the amorphous phase due to the local electric fields in the ferroelectric crystals is proposed. In poled P(VDF‐TrFE), these fields are preferentially aligned resulting in a more stable and higher modulus below the Curie transition. This hypothesis accounts for the lower dielectric signals obtained with the poled sample. Through the Curie transition, the vanishing of these local electric fields, stemming from progressive disorientation and conversion of ferroelectric crystals to paraelectric ones, releases the constraints on the amorphous phase, leading to a storage modulus drop typical of a viscoelastic transition. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1414–1422

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Section: Resultsmentioning

confidence: 89%

Poling influence on the mechanical properties and molecular mobility of highly piezoelectric P(VDF‐TrFE) copolymer

Roggero

Dantras

Lacabanne

2017

J Polym Sci B Polym Phys

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“…This so-called ␤ process is without ambiguity associated with the dynamic manifestation of the glass transition in the amorphous phase of copolymer, i.e., a transition from the glassy to rubbery state. [13][14][15] Earlier studies have shown that the temperature dependence of the characteristic relaxation time of this ␤ relaxation is of the Williams, Landel, and Ferry type, thus being clearly different than the Arrhenius-type relaxation process, which also occurs at low temperatures in the crystalline region of copolymer. 14 ͑ii͒ In the relaxorlike P͑VDF-TrFE͒-based systems up to now only one, broad dispersive maximum has been observed, as shown in our Fig.…”

Section: Resultsmentioning

confidence: 93%

Contributions of distinctive dynamic processes to dielectric response of a relaxorlike reduced poly(vinylidene fluoride-trifluoroethylene) copolymer

et al. 2010

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Dynamic processes in relaxorlike reduced poly͑vinylidene fluoride-trifluoroethylene͒ ͓P͑VDF-TrFE͔͒ copolymer have been studied by measurements of the temperature and frequency-dependent linear and thirdorder nonlinear dielectric response. Dielectric analysis of relaxor polymers has, namely, been incomplete until now, i.e., data interpretation was complicated by the fact that two similar types of dynamics, relaxorlike behavior in the crystalline part of the system and glass-to-rubber transition in the amorphous matrix, take place in the same temperature range and thus superimpose in the detected response. On the other hand, here, in the P͑VDF-TrFE͒ system, synthesized via reductive dechlorination from the poly͑vinylidene fluoride-chlorotrifluoroethylene͒, relaxor peaks take place at much higher temperatures, thus both dynamics can be investigated separately. Analysis of the experimental data reveals that the relaxorlike dielectric dynamics in the reduced P͑VDF-TrFE͒ copolymer, which is now not influenced by processes in the amorphous matrix, indeed is almost identical to that observed in classical relaxor systems and, furthermore, reminiscent of the dynamic behavior observed in various spin glasses. Also, a clear indication was obtained that all polar dynamic processes terminate down to Ϸ100 K and that below this temperature only nonpolar contributions govern the dielectric response of the reduced P͑VDF-TrFE͒ copolymer.

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“…Analysis of dielectric processes in relaxor P(VDF-TrFE)-based systems (electron-irradiated copolymer and terpolymers) has revealed dynamics similar to the one observed in inorganic relaxors and a broad dielectric relaxor peak with high dielectric permittivity (∼40) near room temperature [4]. However, a detailed dielectric analysis of relaxor polymers is complicated by the fact that two similar dynamics, relaxor behavior in the crystalline part of the system and glass-to-rubber transition in the amorphous matrix, take place in the same temperature range and thus superimpose in the detected response [5,6].…”

Section: Introductionmentioning

confidence: 81%

Dielectric Investigations of Relaxor Reduced Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymer in DC Bias Electric Field

et al. 2012

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Properties of newly-developed relaxor reduced poly(vinylidene fluoridetrifluoroethylene) copolymer have been investigated by measurements of temperature and frequency dependent dielectric response in dc bias electric field. It has been found that dc bias field effectively blocks the ac conductivity. The analysis of dielectric dynamics show that the Vogel-Fulcher parameters, obtained from either peaks in ε (T ) or frequency dependent dielectric data, are identical within experimental error. Furthermore, the decrease of Vogel-Fulcher temperature and increase of activation energy on increasing dc bias field suggest that the nonlinear dielectric susceptibility dominantly influences the relaxor dynamics in dc bias electric fields.

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Dielectric relaxation spectra in ferroelectric P(VDF-TrFE) copolymers

Cited by 22 publications

References 29 publications

Poling influence on the mechanical properties and molecular mobility of highly piezoelectric P(VDF‐TrFE) copolymer

Poling influence on the mechanical properties and molecular mobility of highly piezoelectric P(VDF‐TrFE) copolymer

Contributions of distinctive dynamic processes to dielectric response of a relaxorlike reduced poly(vinylidene fluoride-trifluoroethylene) copolymer

Dielectric Investigations of Relaxor Reduced Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymer in DC Bias Electric Field

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