Effect of particle size on electric conducting percolation threshold in polymer/conducting particle composites

The effect of particle size on percolation threshold in polymer/conducting particle composites was studied by analyzing the interparticle distance dependence on particle diameter. It is impossible that the electric path based on the particle contacts appears at percolation, and the electric conduction mainly depends on the electron tunneling effect. When the interparticle distance is shorter than the gap width that quantum tunneling effect permits, percolation takes place. Because interparticle distance decreases proportionally with decreasing particle diameter, the percolation threshold declines with decreasing particle diameters. So long as particle size is small enough, the percolation threshold will be extremely low.