Effect of conductivity of filler on the percolation threshold of composites

Abstract

Polytetrafluoroethylene (PTFE)-silver composites were prepared and the influence of conductivity, particle size, and interfacial area of Ag particle on the percolative behavior were investigated. Silver particles of two different grain sizes (3.5 and 5 μm) were individually mixed with PTFE and the corresponding variations in the dielectric properties were studied. The composite containing Ag particles of size 3.5 μm showed the percolation at 7 vol %, while for Ag particles of size 5 μm, the percolation is at 10 vol %. In both cases near the percolation, the interparticle distances were in the range of ∼3.3–3.8 μm.