Ferroelectric Poly(vinylidene fluoride‐trifluoroethylene‐chlorotrifluoroethylene)s: Effect of Molecular Weight on Dielectric Property

Abstract

A series of ferroelectric poly(vinylidene fluoride-trifluoroethylenechlorotrifluoroethylene), P(VDF-TrFE-CTFE), have been synthesized by a two-step approach. The first step is copolymerization of VDF and CTFE via solution or suspension methods to produce P(VDF-CTFE) copolymers with different molecular weights. The second step is partial de-chlorination to convert copolymers into P(VDF-TrFE-CTFE) terpolymers with precisely controlled compositions. The effect of molecular weight, molecular weight distribution and uniaxially stretching on the dielectric properties has been investigated over a broad range of temperature and frequency. The X-ray diffraction patterns and DSC curves demonstrate the coexistence of the multiple phases in the terpolymers. The dielectric spectra depict the local relaxation processes and relaxor ferroelectric behavior on the basis of the dielectric loss tangent as a function of temperature.

Preparation and crystallization behavior of poly(vinylidene fluoride‐ter‐chlorotrifluoroethylene‐ ter‐trifluoroethylene)

“…However, a major concern in these direct processes is the limited supply of the TrFE monomer, which is dangerous in transport and storage and very expensive 22. Recently, a more convenient chemical route,23–25 including VDF/CTFE copolymerization and partial reduction of chlorine in poly(vinylidene fluoride‐ co ‐chlorotrifluoroethylene) [P(VDF‐ co ‐CTFE)], has been reported to synthesize poly(vinylidene fluoride‐ ter ‐chlorotrifluoroethylene‐ ter ‐trifluoroethylene) [(P(VDF‐ ter ‐CTFE‐ ter ‐TrFE)] terpolymers, and much work has been focused on their electric storage26–28 and dielectric properties 29, 30. Despite previous studies on their electric properties, the crystallization behavior of P(VDF‐ ter ‐CTFE‐ ter ‐TrFE) terpolymers has not been reported in a comprehensive manner.…”

Achieving high mobility, low-voltage operating organic field-effect transistor nonvolatile memory by an ultraviolet-ozone treating ferroelectric terpolymer

“…The XRD pattern of the P(VDF-TrFE-CTFE) film without UVO treatment shows a prominent peak at a 2θ angle of 18°, indicating the (002, 020) reflection faces of ferroelectric phase (Fig. 2b)24. The pentacene film deposited on the P(VDF-TrFE-CTFE) film without UVO treatment exhibited an inferior morphology, with a RMS roughness of 7.10 nm and many small dot-like grains with an average diameter of about 100 nm, as shown in Fig.…”

Considerations of functional fluoropolymer structure in the design of acrylic–fluorine hybrid PSAs: Graft versus telechelic cooligomers

“…So far, constant efforts have been inspired for the functionalization of fluoropolymers to enhance their compatibility with other functional polymers. In families of functionalized approaches, synthetic methods using functional initiators can preserve the intact main‐chain structures of fluoropolymers and meanwhile, create telechelic structures for building blocks to construct complex composites . Ameduri's group utilized the Iodine Transfer Polymerization (ITP) to synthesize a new class of iodine‐terminated fluoropolymers .…”

“…Some teams adopted functional initiators to prepare telechelic fluoropolymers with well‐defined functional end groups which display high thermal stability and uniform dispersibility. These unique initiators include: hydrogen peroxide, functional BPO initiators, fluorinated diester peroxides and functional borane initiators . These effective methods also have some drawbacks.…”