Dielectric characteristics of nano-Ag/SP composite

In order to modify material properties, nano Ag (diameter less than 20 nm) was successfully made from Ag colloidal sol and homogenes dispersed into silicone resin modified polyester (SP). The dielectric properties of the composite were studied. Resistivity-temperature characteristic of the composite is some different from that of pure SP. The maximal breakdown voltage of the composite is 112% of that of pure SP and dielectric loss can be 8 times of pure SP at power frequency. Dielectric constants of the composites all increased with various contents of nano Ag. Two types of shallow traps (0.52 eV and 0.62 eV) with trap densities (1.2×10¹⁰/cm³ and 2.0×10¹¹/cm³) are found in the composite, which differs significantly from those of pure SP (0.58 eV, 3.1×10¹⁰/cm³). Resistivity of the composite is much greater than that of pure SP under cryogenic temperature (77K), which is called Coulomb Blockade effect. From the view of dielectric physics, the different characteristic between the composite and pure SP was discussed and a new concept of nano metal/dielectric materials composite used as device surface protection was introduced.