Percolation onset and electrical conductivity for a multiphase system containing carbon nanotubes and nanoclay

Abstract

The modeling methods estimating the conductivity of multiphase systems are limited. In this article, two simple equations are developed for percolation onset and electrical conductivity of multiphase polymer systems containing carbon nanotubes (CNTs) and nanoclay. The developed equations consider the CNT size, interphase depth, tunneling distance and clay features (clay size and intercalation degree). The estimations of the developed equations exhibit good matching with the experimental data provided from previous articles. Furthermore, all factors play the defensible roles in the percolation onset and conductivity. Thin and large CNTs, thick interphase, big and thin nanoclay and small stacks of nanoclay reduce the percolation onset. The tunneling distance of 1 nm yields the maximum conductivity of 15 S/m, whereas the conductivity decreases to about 0 at tunneling distance of 6 nm. Additionally, narrow CNTs (radius of 5 nm) cause the high conductivity of 1.75 S/m; however the conductivity reduces to 0.2 S/m at CNT radius of 25 nm. The results also show that thin and long nanoclay as well as exfoliated clays are useful to improve the conductivity.