From solvent-cast to annealed and poled poly(VDF-co-TrFE) films: New insights on the defective ferroelectric phase

Bargain, François; Panine, Pierre; Santos, Fabrice Domingues Dos; Tencé‐Girault, Sylvie

doi:10.1016/j.polymer.2016.10.010

Cited by 53 publications

(108 citation statements)

References 43 publications

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“…, ramp 3\). These values are also in good agreement with recent literature . Last, the melt temperature of the depoled material is 2 °C higher than that of the poled one.…”

Section: Resultssupporting

confidence: 92%

“…The first one, respectively situated at T c = 114.2 °C and 106.1 °C on the thermograms 1 and 3, is associated with the ferro‐to‐paraelectric or Curie transition . It is bimodal and, following the studies by Lovinger et al Kim and Kim or Bargain et al, for instance, it can be attributed to the coexistence of a perfect ferroelectric all‐ trans (high‐temperature component) phase and a defective ferroelectric phase containing gauche conformational defects (low‐temperature component). Long range all‐ trans configuration in the crystallites is impossible above T c , resulting in the loss of the ferroelectric property.…”

Section: Resultsmentioning

confidence: 79%

“…Moreover, they are being used as piezoelectric matrixes for multiferroic (magnetoelectric for instance) composites. A recent resurgence of studies on PVDF co‐ and terpolymers probably originates from these prospects of practical applications …”

Section: Introductionmentioning

confidence: 99%

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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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“…, ramp 3\). These values are also in good agreement with recent literature . Last, the melt temperature of the depoled material is 2 °C higher than that of the poled one.…”

Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 79%

See 1 more Smart Citation

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 other maximum correspond to distances between 20 and 37 nm. These dimensions fit well the period of crystalline lamellae observed in this kind of copolymers after annealing 21,23. The sharpest peaks are observed in the Blend‐90/10 (19 and 32 nm) and in Blend‐80/20 (22 and 37 nm).…”

Section: High and Temperature Independent Dielectric Constant Polymersupporting

confidence: 82%

“…P(VDF‐ co ‐TrFE) copolymer containing 54 mol% of TrFE unit has a maximum relative permittivity peak at a temperature of 66 °C and do not depict any thermal hysteresis between heating and cooling, as it is usually observed for the Curie transition 23,24. These features are markers of a defective ferroelectric phase (DFE)23 and is in agreement with the phase diagram reported by Tashiro et al where copolymer containing VDF amount lower than 55% do not exhibit hysteresis 24. For this composition range, relaxor‐ferroelectric (RFE) behavior was reported by Liu et al, once again no thermal hysteresis is observed 25.…”

Section: High and Temperature Independent Dielectric Constant Polymermentioning

confidence: 96%

High and Temperature‐Independent Dielectric Constant Dielectrics from PVDF‐Based Terpolymer and Copolymer Blends

Thuau

Kallitsis

et al. 2020

Adv Elect Materials

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Relaxor ferroelectric polymers exhibit high k at their structural phase transition around room temperature. They are particularly attractive as gate dielectric in organic field effect transistor (OFET). Nevertheless, their applications are limited due to their low thermal stability. A polymer blend system with a high and thermally stable dielectric constant is demonstrated by mixing terpolymer poly(vinylidene fluoride‐trifluoroethylene‐chlorofluorethylene) P(VDF‐ter‐TrFE‐ter‐CFE) with copolymer poly(vinylidene fluoride‐trifluoroethylene) P(VDF‐co‐TrFE). PVDF‐based blends of various compositions are characterized by dielectric spectroscopy, differential scanning calorimetry (DSC), infrared spectroscopy, small and wide angle X‐ray scattering (SAXS and WAXS), and atomic force microscopy (AFM) in order to investigate the relationship between morphology and crystallization of the blend and their dielectric properties. An optimized blend of P(VDF‐ter‐TrFE‐ter‐CFE) [55/37/8] and P(VDF‐co‐TrFE) [46/54] at a ratio of 70/30 is found to exhibit a quasi‐constant dielectric constant of 40 ± 2 over a wide temperature range (20–80 °C). Furthermore, electrical characteristics of the PVDF‐blend‐based gate dielectric OFET show further thermal stability in comparison to OFET based on high‐k terpolymer P(VDF‐ter‐TrFE‐ter‐CFE) [55/37/8]. An improvement of their drain current stability by up to 60% is demonstrated at 60 °C. These findings enable broader applications of fluoropolymers in organic electronics.

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Enhanced Electrocaloric Response of Vinylidene Fluoride–Based Polymers via One‐Step Molecular Engineering

Goupil

Kallitsis

Tencé‐Girault

et al. 2020

Adv Funct Materials

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Electrocaloric refrigeration is one of the most promising, environmentally-friendly technology to replace current cooling platforms-if a notable electrocaloric effect (ECE) is realized around room temperature where the highest need is. Here, we report a straightforward , onepot chemical modification of P(VDF-ter-TrFE-ter-CTFE) through the controlled introduction of small fractions of double bonds within the backbone that, very uniquely, decreases the lamellar crystalline thickness while, simultaneously, enlarging the crystalline coherence along the a-b plane. This increases the polarizability and polarization without affecting the degree of crystallinity or amending the crystal unit cell-undesirable effects observed with other approaches. Specifically, the permittivity increases by >35%, from 52 to 71 at 1 kHz, and ECE improves by >60% at moderate electric fields. At 40 C, an adiabatic temperature change >2 K is realized at 60 MVꞏm-1 (>5.5 K at 192 MVꞏm-1), compared to 1.3 K for pristine P(VDFter-TrFE-ter-CTFE), highlighting the promise of our simple, versatile approach that allows direct film deposition without requiring any post-treatment such as mechanical stretching or high-temperature annealing for achieving the desired performance. Enhanced Electrocaloric Response of Vinylidene Fluoride-based Polymers via One-Step Molecular Engineering

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From solvent-cast to annealed and poled poly(VDF-co-TrFE) films: New insights on the defective ferroelectric phase

Cited by 53 publications

References 43 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

High and Temperature‐Independent Dielectric Constant Dielectrics from PVDF‐Based Terpolymer and Copolymer Blends

Enhanced Electrocaloric Response of Vinylidene Fluoride–Based Polymers via One‐Step Molecular Engineering

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