Thermotropic~Gold~Nanorod~Liquid Crystal Phases*

Large scale, oriented arrays of gold~nanorods~(Au NR) are of interest for a variety of applications, such as negative index materials and hyperbolic dispersion lenses. We report a method for preparing~lyotropic, nematic~LC phases of Au NR by combining polymer coated Au NR with a low molecular weight ($<$ 3200) polymers~solvent. The solvent system was~prepared by reacting hydroxymethyl siloxane and styrene~via a hydrosilylation reaction. At appropriate ratios, these mixtures exhibit liquid crystalline phase behavior. ~Lyotropic LC phases of Au NR were observed for Au NR with aspect ratio above 4, diameter $\sim $15nm, using either linear or cyclic siloxane-styrene polymers as the solvent. Compared with other preparation methods such as lithography or evaporative deposition that produce static films, these self-assembled thermotropic LC phases of Au NR may be re-oriented in response to thermal or electric stimulus.