Liquid crystal suspensions of carbon nanotubes assisted by organically modified Laponite nanoplatelets

We present a simple and effective approach for dispersion of carbon nanotubes (CNTs) into liquid crystals (LCs), suitable for a wide range of CNT concentrations (<= 0.1 wt.%). It consists in doping of LC+CNT suspensions with Laponite, which shows high affinity to the nanotubes. The organo-modified Laponite platelets surround CNTs and hamper their aggregation. At the same time, they do not hinder orientational ordering of CNTs imposed by LC matrix. This approach avoids problems of direct organo-modification of CNTs, associated with worsening of their unique properties. The increased dispersion degree results in drastic changes in dielectric and electro-optical characteristics of the suspensions. Dispersing and insulating effects of the Laponite platelets on CNTs lead to the absence of classical percolation of conductivity, linear growth of dielectric constant with CNT concentration, as well as reduction of Frederiks threshold and significant growth of contrast ratio of the E7+CNTs suspensions. (C) 2013 Elsevier Ltd. All rights reserved.