Dispersion of solvent-wet carbon nanotubes for electrical CNT/polydimethylsiloxane composite

Highly entangled carbon nanotube (CNT) aggregates contain lots of empty spaces formed by entangled nanotubes wherein a viscous fluid has difficultly to diffuse through these spaces without strong driving force. It is necessary to fill the free volume with the matrix before the dispersion of CNTs. This study is focused on the investigation of the solvent wetting effect of CNTs on their dispersion. The heterogeneously distributed narrow and long tunnels, like porous media in entangled clumps, are wetted with a solvent before dispersion. It results in the improved electrical performance of CNT/PDMS composite since the solvent-wet CNTs have reduced surface energy and may improve the dispersion of CNTs under flow. The dispersion of the solvent-wet CNTs may reduce the entangled CNT aggregates since they have sufficient time to wet and the external energy transferred to the composite during dispersion is used only to disperse the CNT aggregate. Also, if the solvent with a low evaporation temperature is chosen, it does not remain in the composite product at all. The solvent-wetting method is suggested as a novel dispersion method having a high potential for industrial applications, from storage of CNTs to dispersion. (C) 2013 Elsevier Ltd. All rights reserved.