Understanding the observation of large electrical conductivity in liquid crystal-carbon nanotube composites

We report the electrical conductivity and dielectric constant measurements in composites of single-walled carbon nanotubes (CNTs) with nematic liquid crystals, employing electrical and magnetic fields as reorienting fields. Our studies demonstrate that the large magnitude of enhancement in the electrical conductivity reported in voltage-driven reorientation measurements is not due to the inherent property of CNTs, and that dielectric breakdown and local heating effects play an important role. The calculated magnitude of the local heating effect is in agreement with the experimental observation including the nematic-isotropic transition caused by such Joule heating.