Influence of shell thickness on the dielectric properties of composites filled with Ag@SiO₂ nanoparticles

Abstract

Flexible polymer composites were frabicated by solution casting method with core-shell structure nanoparticles (Ag cores coated by SiO2 shell). Ag@SiO2 nanoparticles were prepared by a simple Stöber method. The transmission electron microscopy micrographs indicated that the Ag nanoparticles were about 40-55 nm in diameter and the thickness of shell was 5-20 nm. Compared to the pure PVDF-TrFE, the composites exhibited enhanced dielectric constant and lower dielectric loss. Additionally, an improved breakdown field of the comopsites was obtained when the filler content was 10 wt. % with the SiO2 shell thickness of 10 and 20 nm. Futhermore, the effect of shell thickness was investigated and the results showed that dielectric constant and breakdown field increased with increasing shell thickness. All the improved dielectric performance suggest a promising way to fabricate composites for potential applications in electronic devices.

Towards suppressing loss tangent: Effect of SiO2 coating layer on dielectric properties of core-shell structure flaky Cu reinforced PVDF composites

“…To meet this need, in recent years, much efforts have been devoted to develop polymer composites with high-k which attract great attention because of their unique combination of mechanical flexibility and tunable dielectric properties used as capacitor dielectrics, and electroactive materials [9][10][11][12]. Nowadays, the flexible polymeric composites with high-k and low dielectric losses have been increasingly required because of the rapid development of high performance electronic components and electrical equipments, such as energy storage devices, embedded capacitors, artificial muscles and skins, electric accessories, actuators, and other flexible electronics [13][14][15][16][17][18][19].…”

“…Typically, four different strategies have been explored to develop polymer-based composites with excellent dielectric performance: namely, (i) selection of proper polymer matrices; (ii) incorporation of ceramic additives with high dielectric constants; (iii) addition of conductive organics like polymers or oligomers; and (iv) addition of inorganic conductive fillers [4,6,[8][9][10][11][12][13]. So far, Polymer/ferroelectric ceramic composites and polymer/conductive filler percolative dielectric composites are two kinds of research concentrations that are widely studied.…”

“…To overcome the limitations of ferroelectric polymer/ceramic composites, very promising work has been carried out based percolation theory, in which a small volume fraction of conductive filler was added to the polymer matrix to achieve a high-k, thus preserving the mechanical flexibility of the polymer [6, 8-10, 13, 15]. Although these composites can show very high dielectric constants near the percolation threshold (f c ), they still cannot be considered as effective materials for embedded capacitor applications due to the inevitably accompanied huge increase of loss tangent (tanδ), thus imposing considerable challenge and risk in preciously controlling the percolative threshold composition to obtain reproducible products for practical applications [13][14][15]. Therefore, fulfilling the balance between sufficiently high-k and low tanδ is currently still a challenge in obtaining composites with high dielectric performance.…”

“…Currently, one of the trends in this area is to involve core-shell particles as fillers [1,11,13,15].…”

“…Under delicate designing, composites with high-k and low loss could be achieved by controlling and optimizing the microstructure and electrical properties of the core-shell particles [22][23][24]. This type of core-shell structure is usually obtained by chemical synthesis router [1,11,13,15,[18][19][20][21][22][23][24][25][26], such as CNTs@SiO 2 , CNTs@TiO 2 , Ag@TiO2, Ag@SiO2, Ag@C, GNPs@Al 2 O 3 , etc. BT@SiO 2 ,…”