Re-evaluation of the origin of relaxor ferroelectricity in vinylidene fluoride terpolymers: An approach using switching current measurements

Abstract

Relaxor-ferroelectric vinylidene fluoride (VDF)-based terpolymers have attracted increased attention for industrial applications because of their large dielectric constants, low voltage operation for nonvolatile memory, and energy storage capabilities. However, the origin of the relaxor ferroelectricity of VDF-based terpolymers is still under investigation. Here, we investigate the ferroelectric behaviour of thin films of terpolymers of VDF, trifluoroethylene (TrFE), and chlorofluoroethylene (CFE) (P(VDF-TrFE-CFE)) and terpolymers of VDF, TrFE, and chlorotrifluoroethylene (CTFE) (P(VDF-TrFE-CTFE)) using switching current – electric field (I-E) loop measurements. I-E loop measurements have substantial advantages because they directly provide information regarding the independent switching behaviour of dipoles. We show that the I-E loops of P(VDF-TrFE-CFE) are the summation of three pairs of Gaussian peak functions. Moreover, we provide definite proof of the presence of double hysteresis loop-like antiferroelectric behaviour and relaxor-ferroelectricity in the nanodomains of the dipoles when applying positive or negative sinusoidal electric fields to the sample films.

Ferroelectric switching in spin‐coated nylons 11 and 12

“…For the MQ sample, narrower or slimmer P – E hysteresis loops are measured. Similar narrower or slimmer P – E hysteresis loops were also measured for the relaxor‐ferroelectric terpolymer of vinylidene fluoride (VDF), trifluoroethylene (TrFE), and chlorotrifluoroethylene (CTFE) (P[VDF‐TrFE‐CTFE]) . I – E hysteresis loops for the MQ sample of nylon 12 are also similar to those for P(VDF‐TrFE‐CTFE) .…”

“…Similar narrower or slimmer P – E hysteresis loops were also measured for the relaxor‐ferroelectric terpolymer of vinylidene fluoride (VDF), trifluoroethylene (TrFE), and chlorotrifluoroethylene (CTFE) (P[VDF‐TrFE‐CTFE]) . I – E hysteresis loops for the MQ sample of nylon 12 are also similar to those for P(VDF‐TrFE‐CTFE) . Among the nylon 12 samples, the MC sample showed the smallest P r value, which is ascribed to the polarization switching of the smaller γ’ crystal form region in the MC sample, as shown in Figure and Table .…”

“…The switching speed for P(VDF‐TrFE) was taken from the data in Ref. . [Color figure can be viewed at wileyonlinelibrary.com]…”

Reducing leakage current and dielectric losses of electroactive polymers through electro-annealing for high-voltage actuation

“…Fig. 10a shows that the resulting current of the TH sample has a typical feature of a relaxorferroelectric material 59 exhibiting a perfectly symmetrical and linear relationship under voltages of E peak-peak ¼ AE30 V mm À1 . This resistive behavior can be described via Ohms's law:…”

A flexible capacitive photoreceptor for the biomimetic retina

“…On the other hand, polyvinylidene fluoride (PVDF) based ferroelectric polymers have an electroactive phase and are widely used as a dielectric medium in various energy storage applications 41 , fractional-order capacitors 42 , 43 , optoelectronic devices 44 , and plastic solar cells 45 . Especially, a terpolymer of PVDF such as PVDF-TrFE-CFE exhibits a high dielectric constant (high k value), and low dielectric losses 46 , which can offer high capacitance and high dynamic range in the tunability of capacitors. Moreover, it is a relaxor ferroelectric polymer, high charging and discharging efficiencies are achievable for capacitive energy storage applications 47 , 48 .…”