Characterizations and Significantly Enhanced Dielectric Properties of PVDF Polymer Nanocomposites by Incorporating Gold Nanoparticles Deposited on BaTiO3 Nanoparticles

Abstract

Poly(vinylidene fluoride) (PVDF) nanocomposites were fabricated by incorporating BaTiO3 nanoparticles (particle size of ~100 nm, nBT), which were deposited by Au nanoparticles (nAu) with an average particle size of 17.8 ± 4.0 nm using a modified Turkevich method. Systematic characterizations on the synthesized nAu-nBT hybrid nanoparticles and nAu-nBT/PVDF nanocomposites with different contents of a filler were performed. The formation of nAu-nBT hybrid nanoparticles was confirmed with the calculated nAu:nBT ratio of 0.5:99.5 wt.%. The homogeneous dispersion of nAu and nBT in the PVDF polymer was obtained due to the interaction between the negative surface charge of the nAu-nBT filler (compared to that of the nBT) and polar β-PVDF phase, which was confirmed by the zeta potential measurement and Fourier-transform infrared spectroscopy, respectively. A significantly increased dielectric permittivity (ε′ ~ 120 at 103 Hz) with a slight temperature-dependent of <±15% ranging from −20 to 140 °C was obtained. Notably, a low loss tangent (tanδ < 0.08) was obtained even at a high temperature of 140 °C. Therefore, incorporating a PVDF polymer with nAu-nBT hybrid nanoparticles is an attractive method to improve the dielectric properties of a PVDF polymer for dielectrics applications.

High-k Three-Phase Epoxy/K1.6(Ni0.8Ti7.2)O16/CNT Composites with Synergetic Effect

“…In the case of a composite with the highest CNT concentration (0.425 vol.%), a significant increase in ε′ in comparison with the initial polymer matrix and composites with different compositions is associated with an increase in the conductivity of the system after overcoming the percolation threshold, which is also confirmed by the frequency dependences of the conductivity ( Figure 11 ). The obtained permittivity values of (Epoxy-CNT 0.213%)-KNTO 19.5% and (Epoxy-CNT 0.425%)-KNTO 18.9% are comparable to the results for the composite with the composition Au–BaTiO 3 /PVDF (grey section in Figure 10 b) [ 42 ].…”

“…The introduction of K 1.6 (Ni 0.8 Ti 7.2 )O 16 without a conductive additive and with CNTs in an amount of 0.213 vol.% in the epoxy resin gives the same trend in the frequency dependences of the dielectric loss tangent, exceeding the value of tanδ of ED-20 only in the low-frequency range (~10 2 Hz). Dielectric losses of the obtained three-phase composites with low CNT content are in the range typical for similar composite Au–BaTiO 3 /PVDF (grey section in Figure 12 b) [ 42 ].…”

“… The frequency dependence of permittivity ( a ) two- and ( b ) three-phase composites compared to pure epoxy resin. Color areas in this Figure: ( a ) numerical simulation for similar two-phase composites [ 41 ], ( b ) experimental data for similar three-phase composite [ 42 ]. …”

“… The frequency dependence of the dielectric loss tangent of ( a ) two- and ( b ) three-phase composites in comparison with the pure epoxy resin. Grey section in Figure 12 b is experimental data for similar three-phase composite [ 42 ]. …”

Strategies Involved in Enhancing the Capacitive Energy Storage Characteristics of Poly(vinylidene fluoride) Based Flexible Composites

“…which could be effectively utilized to enhance the polarity of PVDF. Among all these techniques, the inclusion of ceramic material in the PVDF matrix is being widely adopted by the researchers all over the world because this technique not only improves the polarity of the PVDF based composite systems but also greatly improves the effective dielectric constant of the composites without significantly reducing the electric breakdown strength [118–120] . Thus the energy storage performance improves accordingly.…”