Influence of interface on the electrical properties of silicone nanocomposites

The interface between filler and matrix affects the properties of nanocomposites because of the high ratio of surface area to volume of nano fillers. To understand the role of interface, silicone nanocomposites containing two different types of hydrophobic fumed silica with different specific surface areas of 160 and 260 m 2 /g in silicone rubber (RTV 615) matrix are investigated using frequency domain spectroscopy. The spectroscopy measurements are carried out in the frequency range of 10 −4 to 10 3 Hz, at various excitation levels. Effects of filler concentration, filler surface treatment, and mixing method on the dielectric properties are investigated. The results show that the level of filler dispersion plays a major role in determining the effective permittivity and loss factor as it considerably alters the volume of interface region and bonding of fillers to the polymer.