https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 05 Jun 2026 22:15:24 GMT 2026-06-05T22:15:24Z http://hdl.handle.net/10985/18384 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 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. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18384 2020-01-01T00:00:00Z THUAU, Damien KALLITSIS, Konstantinos HA, Sara BARGAIN, François SOULESTIN, Thibaut PÉCASTAINGS, Gilles TENCÉ-GIRAULT, Sylvie DOMINGUES-DOS SANTOS, Fabrice HADZIIOANNOU, Georges 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. http://hdl.handle.net/10985/17957 Introducing Functionality to Fluorinated Electroactive Polymers KALLITSIS, Konstantinos; SOULESTIN, Thibaut; TENCÉ-GIRAULT, Sylvie; BROCHON, Cyril; CLOUTET, Éric; DOMINGUES-DOS SANTOS, Fabrice; HADZIIOANNOU, Georges 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 appropriate for vastly different applications in electronics. However, due to the chemical inertness of such polymers and the rather complex synthetic processes required for their production, introducing additional functionality to FEPs remains an open challenge. Here, we present a facile way to introduce additional functionality to FEPs and more specifically photopatternability by a simple etherification method, which allows us to introduce almost any functional group on FEPs. Photo-cross-linkable moieties were introduced on FEPs using this method, inducing photopatternability, while tuning their electroactive response with great property enhancement up to 60% in terms of relative permittivity in several cases. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/17957 2019-01-01T00:00:00Z KALLITSIS, Konstantinos SOULESTIN, Thibaut TENCÉ-GIRAULT, Sylvie BROCHON, Cyril CLOUTET, Éric DOMINGUES-DOS SANTOS, Fabrice HADZIIOANNOU, Georges 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 appropriate for vastly different applications in electronics. However, due to the chemical inertness of such polymers and the rather complex synthetic processes required for their production, introducing additional functionality to FEPs remains an open challenge. Here, we present a facile way to introduce additional functionality to FEPs and more specifically photopatternability by a simple etherification method, which allows us to introduce almost any functional group on FEPs. Photo-cross-linkable moieties were introduced on FEPs using this method, inducing photopatternability, while tuning their electroactive response with great property enhancement up to 60% in terms of relative permittivity in several cases. http://hdl.handle.net/10985/19488 Enhanced Electrocaloric Response of Vinylidene Fluoride–Based Polymers via One‐Step Molecular Engineering LE GOUPIL, Florian; KALLITSIS, Konstantinos; TENCÉ‐GIRAULT, Sylvie; POURIAMANESH, Naser; BROCHON, Cyril; CLOUTET, Eric; SOULESTIN, Thibaut; DOMINGUE DOS SANTOS, Fabrice; STINGELIN, Natalie; HADZIIOANNOU, Georges 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. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19488 2020-01-01T00:00:00Z LE GOUPIL, Florian KALLITSIS, Konstantinos TENCÉ‐GIRAULT, Sylvie POURIAMANESH, Naser BROCHON, Cyril CLOUTET, Eric SOULESTIN, Thibaut DOMINGUE DOS SANTOS, Fabrice STINGELIN, Natalie HADZIIOANNOU, Georges 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.