Enhancement of electrical conductivity of a liquid crystal-gold nanoparticle composite by a gel network of aerosil particles

Abstract

We report electrical conductivity measurements on a pure nematic liquid crystal (LC) and its composites comprising Gold nanoparticles (GNPs) as well as aerosil particles. The inclusion of aerosil particles creating a gel network, albeit being non-conducting, surprisingly enhances the already high conductivity of the LC-GNP material. The presence of aerosil also makes the frequency dependence of the conductivity compatible with the universal phenomenon expected for disordered solids despite the LC confined in the network is still a liquid. The nature of the aerosil corona (hydrophobic/hydrophilic) also controls the behavior. We argue that these features are caused by the amelioration of the percolation network of GNPs through the primary gel network of the hydrogen bonding aerosil particles. The concept can be generalized for a variety of systems wherein metal nanoparticles are embedded in an insulating matrix.