Enhanced Electrocaloric Response of Vinylidene Fluoride–Based Polymers via One‐Step Molecular Engineering
TypeArticles dans des revues avec comité de lecture
Electrocaloric refrigeration is one of the most promising environmentally-friendly technologies to replace current cooling platforms—if a notable electrocaloric effect (ECE) is realized around room temperature where the highest need is. Here, a straight-forward, one-pot chemical modification of P(VDF-ter-TrFE-ter-CTFE) is reported 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 MV m−1 (>5.5 K at 192 MV m−1), compared to ≈1.3 K for pristine P(VDF-ter-TrFE-ter-CTFE), highlighting the promise of a 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.
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KALLITSIS, Konstantinos; SOULESTIN, Thibaut; TENCÉ-GIRAULT, Sylvie; BROCHON, Cyril; CLOUTET, Éric; DOMINGUES-DOS SANTOS, Fabrice; HADZIIOANNOU, Georges P. (American Chemical Society, 2019)Fluorinated electroactive polymers (FEPs) are among the most interesting insulating materials for the production of organic electronic devices. Their ability to tune their response to an applied electric field makes them ...
High and Temperature-Independent Dielectric Constant Dielectrics from PVDF-Based Terpolymer and Copolymer Blends THUAU, Damien; KALLITSIS, Konstantinos; HA, Sara; BARGAIN, François; SOULESTIN, Thibaut; PÉCASTAINGS, Gilles; TENCÉ-GIRAULT, Sylvie; DOMINGUES-DOS SANTOS, Fabrice; HADZIIOANNOU, Georges P. (Wiley, 2020)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 ...
Thermal behavior of poly(VDF-ter-TrFE-ter-CTFE) copolymers: Influence of CTFE termonomer on the crystal-crystal transitions BARGAIN, François; THUAU, Damien; PANINE, Pierre; HADZIIOANNOU, Georges; DOMINGUES DOS SANTOS, Fabrice; TENCE-GIRAULT, Sylvie (elsevier, 2019)Depending on their CTFE content (from 0 to 10 mol %), poly (VDF-ter-TrFE-ter-CTFE), poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) copolymers exhibit ferroelectric (FE) or relaxor ferroelectric ...
Influence of Field-Induced Phase Transition on Poly(Vinylidene Fluoride-Trifluoroethylene-Chlorotrifluoroethylene) Strain LHERITIER, P.; VAXELAIRE, N.; TENCE-GIRAULT, Sylvie; DOMINGUES DOS SANTOS, F.; DEFAY, E. (American Physical Society, 2020)This work is focused on understanding the reasons behind the large electrostrictive strain of poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymer. Although a few explanations have been proposed ...
Simultaneous SAXS-WAXS experiments on semi-crystalline polymers: Example of PA11 and its brill transition TENCÉ-GIRAULT, Sylvie; LEBRETON, Sylvie; BUNAU, Oana; DANG, Patrick; BARGAIN, François (MDPI, 2019)This manuscript of the special issue “Microstructural Evolution and Mechanical Behavior of Semi-Crystalline Polymers” aims to show that Small Angle X-ray Scattering (SAXS) and Wide Angle X-ray Scattering (WAXS) experiments ...