The Effects of Morphology of Ag@SiO2 Core-Shell Nanoparticles on the Dielectric Properties and Mechanical Properties of Polyvinylidene Difluoride Based Nanocomposite

In this report, two kinds of Ag@SiO2 core-shell structured nanoparticles were prepared with linear and cubic morphologies. Subsequently, a series of polyvinylidene difluoride (PVDF) based nanocomposites were prepared by blending the Ag@SiO2 nanoparticles mechanically into the PVDF. The surface morphology and core-shell structure of the Ag@SiO2 nanoparticles and their dispersed states in the PVDF matrix were investigated using scanning and transmission electron microscopy (SEM and TEM). In addition, the influence of the Ag@SiO2 nanoparticles on the dielectric properties of the nanoparticles were studied over a wide range of testing frequencies and these results showed that the dielectric constant of the nanocomposites increased sharply with an increase in filler content. For example, when the Ag@SiO2 nanoparticles were added at a concentration of 20 wt%, the nanocomposites containing cubic and wires-like particles exhibited a dielectric constant of 11.7 and 14 respectively at 100 Hz. At the same time, the breakdown field strength of composites increased while the dielectric loss did not increase significantly. The effect of Ag@SiO2 nanoparticles on the mechanical properties of nanocomposites was also studied and showed that the addition of filler did not reduce the energy storage modulus of the composite material.