Dielectric properties of Ag@C/PVDF composites

The core-shell Ag@C nanoparticles were prepared by hydrothermal method. The silver cores with diameters from 100 to 120 nm are each covered with a carbon shell about 60-80-nm thick. Ag@C/poly(vinylidene fluoride) (PVDF) composites were prepared by the solution cast method. Transmission electron microscopy showed that the Ag@C core-shell nanoparticles were dispersed homogenously in the PVDF matrix with little agglomeration. The crystallization behavior and dielectric properties of the Ag@C/PVDF composites as a function of frequency and temperature were studied. The differential scanning calorimeter measurements showed that the crystallinity of the Ag@C/PVDF composites decreased with the increasing content of the Ag@C nanoparticles. The dielectric tests showed that the permittivity of the Ag@C/PVDF composites increased obviously over that of the pure PVDF with increasing content of Ag@C particles because of the enhanced interfacial polarization. The tan of the composites remained at a low level (approximate to 0.08 at 1000 Hz). Furthermore, the permittivity and the tan of the composites increased with increasing temperature. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013