Core@Double–Shell Engineering of Zn Particles toward Elevated Dielectric Properties: Multiple Polarization Mechanisms in Zn@Znch@PS/PVDF Composites

Abstract

Flexible dielectrics with large dielectric constant (ε′) coupled with low loss are highly pursued in many applications. To bolster the ε′ of raw Zn (zinc)/poly(vinylidene fluoride, PVDF) while maintaining pimping dielectric loss, in this study, the core@double–shell structured Zn@zinc carbonate (ZnCH)@polystyrene (PS) particles are first synthesized through a suspension polymerization of styrene, and then composited with PVDF to elevate the ε′ and keep low loss of the composites. By optimizing the PS shells’ thickness and tailoring the electrical resistivity of Zn@ZnCH@PS particles, both the slow inter‐particle polarization and fast intra‐particle polarization in the composites can be decoupled and synergistically tuned, thus, the Zn@ZnCH@PS/PVDF achieves a much higher ε′ and lower dielectric loss, simultaneously, which far exceed the unmodified Zn/PVDF. Both experiment and theoretic calculation reveal that the double‐shell ZnCH@PS not only induces and promotes multiple polarizations enhancing the composites’ ε′, especially at the optimized PS's thickness, but also maintains suppressed loss and conductivity thanks to their obvious barrier effect on long‐range charge migration. The core@double–shell filler design strategy facilitates the development of polymer composites with desirable dielectric properties for applications in electronic and electrical power systems.

Polyimide Composites with Fluorinated Graphene and Functionalized Boron Nitride Nanosheets for Heat Dissipation

“…In a previous study, the change of dielectric loss is closely related to the electrical conductivity and the trend of their change is basically the same. The coating of PDA on the surface of the filler results in a rich covalent interface between BNNS and PI, which may form an efficient insulating barrier to hinder the flow of charge carrier, leading to a decrease in the leakage current and reducing the dielectric loss of the composites. , Additionally, the overlap interface can be obtained by the interface interaction of adjacent fillers, reducing the free volume of PI molecular chain, so as to better suppress the interface loss and conductivity loss . In general, tan δ of all of the FG/PDA@BNNS/PI composite films is below 0.014 at 1 MHz in Figure f.…”

Heterostructured Alumina/Boron Nitride Nanosheets for Thermal Management of Poly(dimethylsiloxane)

“…The PDMS matrix is the primary factor that determines its electrical resistivity volume. The contact probability between f-A@B rises with an increase in f-A@B amount, forming more carrier transport paths and improving the electrical resistivity volume of the f-A@B/PDMS thermally conductive composite film. , In short, the measured volume resistivity exceeds the electrical insulation threshold resistance (10 9 Ω cm) by over 4 orders of magnitude.…”

“…The contact probability between f-A@B rises with an increase in f-A@B amount, forming more carrier transport paths and improving the electrical resistivity volume of the f-A@B/PDMS thermally conductive composite film. 59,60 In short, the measured volume resistivity exceeds the electrical insulation threshold resistance (10 9 Ω cm) by over 4 orders of magnitude. The thermal stability of the f-A@B/PDMS thermally conductive composite films was evaluated using thermal gravimetric analysis (TGA).…”

Facile preparation of thermally conductive fiber film by self‐assembling interconnected boron nitride nanosheets for effective thermal interface materials

“…41,42 A broad peak could be clearly watched at around 3250 cm À1 due to the stretching vibrations of -OH for both of BN and XG. 43,44 The XRD diffraction pattern illustrated in Figure 2F presents BN structure with a characteristic peak at around 27 , which is due to the crystallographic plane (002) of BN. The XG shows several broad peaks, which means the XG is an amorphous polymer.…”