Interfacial Effect on Dielectric Properties of Polymer Nanocomposites Filled with Core/Shell-Structured Particles

• Published in: Advanced functional materials Vol. 17; no. 14; pp. 2405 - 2410
• Main Authors: Shen, Y., Lin, Y. H., Nan, C.-W.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 24-09-2007; WILEY‐VCH Verlag
• Subjects: Composites; Composites, polymer; Conductivity; Conductivity, electrical; Core/shell nanoparticles; Dielectrics; electrical; Epoxy; polymer; Silver; Solution processing
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200700200

Novel polymer nanocomposites were prepared by solution processing with core/shell structured nanoparticles (carbonaceous shell coating on silver cores) as fillers. The organic carbonaceous shells act as interlayers between the Ag cores as well as with the polymer matrix. It is shown that the electrical properties of the interlayers play a dominative role in determining the dielectric behavior of the nanocomposites. Insulating interlayers reduce the tunnel current between neighboring Ag cores by causing potential barriers, endowing the nanocomposites with stable and high dielectric constants and low dielectric loss. Furthermore, the stable dielectric constants of the nanocomposites could be tuned by adjusting the thickness of the interlayers. Increasing the conductivity of the interlayers lowers the potential barriers, making the dielectric behavior of the nanocomposites more similar to that of conventional percolative composites.
Polymer nanocomposites were prepared with Ag@C core/shell nanoparticles as fillers. The shell acts as an interlayer between metal cores, and its electrical properties play a dominative role in determining the dielectric behavior of the nanocomposites (see figure, which shows the effect of Ag@C volume fraction f on the dielectric constant ϵ of the composite).