Influence of trans-1,3,3,3-Tetrafluoropropene on the Structure–Properties Relationship of VDF- and TrFE-Based Terpolymers

Abstract

trans-1,3,3,3-Tetrafluoropropene (1234ze) was copolymerized under free radical conditions with vinylidene fluoride (VDF) and trifluoroethylene (TrFE), for the first time, leading to statistical poly(VDF-ter-TrFE-ter-1234ze) electroactive terpolymers. The reactivity ratios of the three comonomer couples were determined (r VDF = 0.77; r TrFE = 0.32), (r VDF = 1.67; r 1234ze = 0.00), and (r TrFE = 7.56; r 1234ze = 0.00), at 48 °C, using the nonlinear fitting Mayo−Lewis method. 1234ze was shown to be regularly incorporated in the terpolymer chains over the entire course of the reaction providing terpolymer chains with statistical monomer distribution and almost constant composition. These new VDF/TrFE-based terpolymers were characterized by 1 H and 19 F liquid state NMR spectroscopy. The characteristic NMR signals of the VDF− 1234ze dyads were identified by comparing the NMR spectral signatures of a poly(VDF 82 -co-1234ze 18 ) copolymer and of a terpolymer. The thermal and electroactive properties of poly(VDF-ter-TrFEter-1234ze) terpolymers, with 1234ze content ranging from 0 to 6 mol % and molar masses above 55 kg/mol, were assessed. The randomly distributed 1234ze termonomer units induced the decreases of both the Curie and the melting temperatures of the terpolymer even at low termonomer content (T Curie = 70 °C and T m = 126 °C and T Curie = 72 °C and T m = 150 °C; for a poly(VDF 69 -ter-TrFE 28 -ter-1234ze 3 ) terpolymer and a poly(VDF 65 -co-TrFE 35 ) copolymer, respectively). Films of the terpolymers were cast, and their electroactive properties were examined by D−E loops measurements. They showed that the presence of 1234ze decreased the remnant polarization (P r = 45 mC/m 2 for a poly(VDF 65 -co-TrFE 35 ) copolymer to 28 mC/m 2 for a poly(VDF 69 -ter-TrFE 25 -ter-1234ze 6 ) terpolymer) probably because it also decreased the crystallinity of the terpolymer. The combination of the studies of the reactivity of the monomers, of the terpolymer microstructures, and of the assessment of their physical properties provides insights into their structure−property relationship.

Electroactive materials with tunable response based on block copolymer self-assembly

“…Introduction of extra functionalities into the structure of ferroelectric polymers can further widen their application in related fields 6–10 . The response of PVDF-based polymers to an applied electric field can be altered from ferroelectric to relaxor or even linear dielectric by the adjustment of the crystalline domain size or by screening the nominal electric field values inside the crystalline ferroelectric phase 11–17 . Thus, it would be highly beneficial to develop a simple method that can simultaneously tailor the hysteresis shape while adding a new functionality.…”

Design, synthesis and processing of PVDF‐based dielectric polymers

“…The introduction of much bulkier monomers with the CF 3 pendant group such as HFP, 3,3,3-trifluoropropene (TFP), 2,3,3,3tetrafluoropropene (1234yf), and trans-1,3,3,3-tetrafluoropropene (1234ze) into the VDF-TrFE chain could also decrease the crystal size and lead to some changes in the FE properties [75][76][77][78]. It should be noted that, despite the modification of the crystal lattice, these terpolymers still exhibit normal FE behaviour as the bulky CF 3 group is too large to be incorporated inside the crystals.…”

Tuning the dielectric behavior of poly(vinylidene fluoride-co-vinyl alcohol) using a facile urethane-based crosslinking method

“…trifluoroethylene (TrFE), hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE) and chlorofluoroethylene (CFE)) have been employed to introduce defects in the polymer backbone and to increase the crystal lattice spacing for enhancing the dipole reversibility. [13][14][15][16][17][18][19] The weak (in poly (VDF-ter-TrFE-ter-CFE)) and strong (in poly(VDF-ter-TrFE-ter-CTFE)) so-called physical pinning spots result in antiferroelectric-like and relaxor ferroelectric behaviors, respectively, increasing the charge-discharge efficiency while still having a high polarization. 20 Interestingly, chemical crosslinking via electron beam irradiation of poly(VDF-co-TrFE) or hot pressing of poly(VDF-co-CTFE) using peroxides and crosslinking agents proves to be a valuable method to achieve slim polarization hysteresis.…”