Ferroelectric polymers with large electrostriction; based on semicrystalline VDF/TrFE/CTFE terpolymers

Abstract

This paper discusses a new ferroelectric polymer with large electrostrictive response (-4%) at ambient temperature, which is based on a processable semicrystalline terpolymer comprising vinylidene difluoride (VDF), trifluoroethylene (TrFE), and chlorotrifluoroethylene (CTFE). This VDFITrFEICTFE terpolymer was prepared by a combination of bulk polymerization process and a borane/oxygen initiator at ambient temperature. The incorporated bulky CTFE units in the terpolymer seem to reduce the crystalline domain size and move the ferroelectric-paraelectric (F-P) phase transition to near ambient temperature with a very small energy barrier. Some terpolymers exhibited common ferroelectric relaxor behaviors with a broad dielectric peak that shifted toward higher temperatures as the frequency increased, and a slim polarization hysteresis loop at near the dielectric peak (around ambient temperature) that gradually evolved into a normal ferroelectric polarization hysteresis loop with reduced temperature.

Significantly improving dielectric and energy storage properties via uniaxially stretching crosslinked P(VDF-co-TrFE) films

“…It has also been found that by introducing defects into P(VDF-co-TrFE), the copolymer could be converted from a normal ferroelectric to a relaxor ferroelectric characterized with signicantly reduced P r and dramatically improved U e . The defects could be introduced either chemical-physically (high energy electron irradiation 20 ) or chemically (copolymerization with a third bulky monomer [21][22][23][24][25] ). The introduction of the third bulky monomer, such as chlorotriuoroethylene (CTFE), 1,1-chlorouoroethylene (CFE) or hexauoropropylene (HFP), as crystalline defects into P(VDF-co-TrFE), may decrease their crystal domain size and crystallinity effectively.…”

Controlled hydrogenation of P(VDF-co-CTFE) to prepare P(VDF-co-TrFE-co-CTFE) in the presence of CuX (X = Cl, Br) complexes

“…[1][2][3] In an effort to increase the dielectric response of these ferroelectric polymers at room temperature, several approaches have been successfully developed. [4][5][6][7][8] Chemically incorporating the third monomer (chlorotrifluoroethylene (CTFE), chlorodifluoroethylene (CDFE)) directly or indirectly into the VDF/TrFE sequence is one of the most effective ways. 7,8 As a result, the resultant terpolymer (P(VDF-co-CTFE-co-TrFE)) exhibits fairly high dielectric constant (> 60) and energy density (> 12 J cm À3 in an electric field of 500 MV m À1 ), [9][10][11] which is highly expected to serve as a dielectric material of high energy density capacitors.…”

“…[4][5][6][7][8] Chemically incorporating the third monomer (chlorotrifluoroethylene (CTFE), chlorodifluoroethylene (CDFE)) directly or indirectly into the VDF/TrFE sequence is one of the most effective ways. 7,8 As a result, the resultant terpolymer (P(VDF-co-CTFE-co-TrFE)) exhibits fairly high dielectric constant (> 60) and energy density (> 12 J cm À3 in an electric field of 500 MV m À1 ), [9][10][11] which is highly expected to serve as a dielectric material of high energy density capacitors. Comparing with the terpolymer synthesized directly from the polymerization of VDF, TrFE and CTFE monomers, the post-terpolymer prepared from the hydrogenation of P(VDF-co-CTFE) copolymer has advantages such as low cost, homogeneous composition distribution and tuneable composition.…”

Synthesis of unsaturation containing P(VDF‐co‐TrFE‐co‐CTFE) from P(VDF‐co‐CTFE) in one‐pot catalyzed with Cu(0)‐based single electron transfer living radical polymerization system

“…The large remnant polarization in the normal ferroelectric PVDF and P(VDF‐ co ‐TrFE) renders a small discharged energy density at zero electric field although the polymers display a high saturation electric displacement (∼0.1 C/m 2 ). Two ways have been successfully developed to reduce the remnant polarization via introducing defects in the crystalline phase of polymer films with either high energy irradiation or copolymerizing with a third bulk monomer . Comparing with irradiation method, the polymer prepared via introducing the third monomer such as chlorotrifluoroethylene (CTFE), chlorodifluoroethylene (CDFE), hexafluoropropylene (HFP), and internal unsaturation as defects into P(VDF‐ co ‐TrFE) may decrease their crystal domain size and crystallinity effectively, which is expected to provide the resultant polymer of high material stability, uniformity, and processing convenience.…”