Percolative multi-susceptible PVDF/NZFO composite films with triply controlled high dielectric and magnetic properties

Abstract

Flexible multi-field susceptible films with remarkable properties and high data storage characteristics are promising in modern electronics. In this work, the percolative Ni0.5Zn0.5Fe2O4 (NZFO)/polyvinylidene fluoride (PVDF) composite films with both high permittivity and significant magnetic properties are prepared by dip coating on ITO/glass substrates. The highest permittivity of 74 is achieved with the NZFO volume ratio close to the percolation threshold, which is 20 times higher than that of pure PVDF. Meanwhile, the dielectric loss is kept below 0.1. The saturation and remanent magnetizations of composite films are 42.04 and 5.70 emu/g and the permeability is ∼3.105, reaching 60%–80% of those in the single phase NZFO. Detailed analysis shows that the high permittivity of the composite film is triply controlled simultaneously by the intrinsic characteristic of the PVDF phase, Kirkpatrick's hybridization model and microcapacitor behavior. It will be of broad interest to control both high dielectric and magnetic properties at the same time of many other flexible and susceptible storage devices.

Multifunctional poly(vinylidene fluoride–co‐hexafluoropropylene) ‐ zinc stannate nanocomposite for high energy density capacitors and piezo‐phototronic switching

“…Figure 4a indicates that the dielectric constant of nanocomposite enhances with increase in filler concentration. 52 Dielectric constant of PNC0 sample was measured to be 6.3 with corresponding loss tangent of 0.12 at 1 kHz frequency, while with increase in filler concentration, dielectric constant of ZnSnO 3 (ZSO) and polymer nanocomposite structure enhanced from 6.3 to 12.2 and loss tangent decreased from 0.12 to 0.06 (Figure 4b) with increase in ZSO filler concentration from 0 to 1 wt % (Table 2). This change in dielectric constant and loss tangent value indicates uniform distribution of filler in polymer matrix, where very low ( ≤ 1%) filler concentration was used to avoid percolation threshold and agglomeration of filler in the polymer matrix.…”

Effect of Carbonate Source on the Dehydrofluorination Process in Polyvinylidene Fluoride/Alkali Metal Carbonate Composites

“…In recent years, polyvinylidene fluoride (PVDF)-based ceramic–polymer composites have attracted intensive attention for flexible energy storage/electronics applications, taking advantage of its high flexibility, low mechanical impedance, and low dielectric loss. − For composites with conductive and dielectric phases, inner microcapacitors can be formed in a series along an external field, in which the conductive phases act as electrodes and the dielectric phases are insulating media . In a previous paper, we have reported that percolative composites consisting of potassium carbonate dispersed in polyvinylidene fluoride (PVDF) polymeric matrix showed a rather high dielectric constant and electrical conductivity at the percolation threshold (30 wt % K 2 CO 3 ) due to the formation of chemically activated interfaces in the composite, as interfacial polarization resulted in high values of dielectric permittivity .…”

“… 1 − 3 For composites with conductive and dielectric phases, inner microcapacitors can be formed in a series along an external field, in which the conductive phases act as electrodes and the dielectric phases are insulating media. 1 In a previous paper, we have reported that percolative composites consisting of potassium carbonate dispersed in polyvinylidene fluoride (PVDF) polymeric matrix showed a rather high dielectric constant and electrical conductivity at the percolation threshold (30 wt % K 2 CO 3 ) due to the formation of chemically activated interfaces in the composite, 4 as interfacial polarization resulted in high values of dielectric permittivity. 5 Further studies revealed the presence of a complex reaction loop for the formation of activated carbon (AC) from PVDF dehydrofluorination during thermal treatment, as the net effect of these reactions is to generate a carbon-based nanocomposite in the polymer matrix.…”