Electrical properties of nano-silver/polyacrylamide/ethylene vinyl acetate composite

Nano-Ag particles/polyacrylamide (PAM) composites were synthesized by γ irradiation method and then blended with ethylene vinyl acetate (EVA). Dielectric behaviors of the Ag/PAM/EVA composites are investigated as a function of both the concentration and size of Ag particles. When concentration of the Ag fillers is rarely low, dielectric anomalies were first observed in contrast to the traditional percolation theory. As concentration of Ag increases, volume resistivity and breakdown field strength are enhanced, loss tangent (tan δ) reduced and dielectric constant kept invariable. In addition, the above variation became larger when the diameter of the Ag nano-particles is smaller. Such dielectric anomalies may be understood by considering the unique “Coulomb Blockade Effect” of the nano-sized Ag particles.