Regular Article

Optimization and control of dynamic percolationin nanostructured silicon oils^*

¹ Université Savoie Mont Blanc, LEPMI, 73000 Chambéry, France
² CNRS, LEPMI, 38000 Grenoble, France
³ Nexans Research Center, 29 rue Pré Gaudry, 69007 Lyon Cedex 07, France

^a e-mail: badardmathieu@gmail.com

Received: 12 December 2016
Revised: 13 April 2017
Accepted: 18 April 2017
Published online: 14 June 2017

Abstract

The addition of carbonaceous fillers in polymers allows the conception of composites with optimized electrical properties. The conductivity of such material depends of the fillers structuration in matrix, especially the presence of percolated network. The objective of this paper is to understand the main aggregation mechanisms of carbon nanotubes in different media. The structuration of these filler network is probed by the use of electrical and dielectrical measurements. The innovative part of our work lies in the use of liquid matrices, especially silicon oils, to overcome mechanical constraints present in polymers on the one hand and to simplify processing on the other hand. Our work has revealed a filler aggregation over time, well known as dynamic percolation. Conductivity has been modeled as a function of time and filler content from Kirkpatrick equation. The further use of an electrical field led to conductivity enhancement as well as a decrease in percolation threshold. Finally, a study of intrinsic parameters of matrix has shown a strong effect of viscosity and surface tension on nanotubes aggregation.