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

Florian Le Goupil (1, 2) , Konstantinos Kallitsis (1, 2) , Sylvie Tencé‐girault (3, 4) , Naser Pouriamanesh (1, 2) , Cyril Brochon (1, 2) , Eric Cloutet (1, 2) , Thibaut Soulestin (5, 6) , Fabrice Domingues dos Santos (5, 6) , Natalie Stingelin (7, 1, 2) , Georges Hadziioannou (1, 2)

1 LCPO - Laboratoire de Chimie des Polymères Organiques
2 Team 4 LCPO : Polymer Materials for Electronic, Energy, Information and Communication Technologies
3 PIMM - Laboratoire Procédés et Ingénierie en Mécanique et Matériaux
4 CERDATO - Centre de recherche, développement, applications et technique de l'ouest
5 Piezotech SAS - Piezotech SAS
6 Arkema - Arkema
7 Georgia Institute of Technology [Atlanta]

Electrocaloric refrigeration is one of the most promising, environmentallyfriendly technology 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-rFE-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.

Mots clés: electrocaloric effect; ferroelectric polymer; microstructure tuning

Domaines: Polymères

Florian Le Goupil, Konstantinos Kallitsis, Sylvie Tencé‐girault, Naser Pouriamanesh, Cyril Brochon, et al.. Enhanced Electrocaloric Response of Vinylidene Fluoride–Based Polymers via One‐Step Molecular Engineering. Advanced Functional Materials, 2020, pp.2007043. ⟨10.1002/adfm.202007043⟩. ⟨hal-02947775⟩