Fabrication of novel, structured, bimodal particle and CNT composites, with low percolation thresholds.

In the segregated network theory of electrical percolation the structure of the conducting network dictates the volume of filler required to reach percolation. 2000 thousand years ago Appollonius of Perga showed that successively smaller circles would fill the interstices of larger circles. In the early 20th century Furnas described how by using a bimodal particle system it was possible for particles to pack in the same way as described by Appollonius and so create materials with a high density and low void fractions. By applying this theory to CNT-Latex composites, it has been possible to force CNTs to fill this reduced void space and so form a connected network at a much lower volume of filler and hence produce films with very low percolation thresholds. This work has also shown the direct dependence of the percolation threshold on the void fraction of the matrix and so can be controlled more effectively through particle choice.