How is electrical percolation achieved in nano doped materials? Direction towards more efficient doping

Abstract

One route to create electrically conductive polymeric material is to dope them using highly conductive nanoparticles such as carbon nanotubes. It is well known that, when a threshold volume fraction is reached, a percolated network is achieved in which efficient conduction can take place. In such a network, inter particles charge transfer takes place over a very short distances, when particles become close enough to each other so a tunneling mechanism becomes possible. It follows that most of the introduced particles are not linked to the percolated path, thus not participating in the doping mechanism. The spatial arrangement of the particles plays a major role in the way they are participating in the increase in macroscopic electrical conductivity. We propose here to go further than the usual method of quantifying filler content based on weight/volume fractions by studying in detail the topology of the particle arrangement. This provides an in-depth understanding about how the conductive path develops when increasing the filler content and paves the way for an optimal use of the doping particles.