Controlled orientation and order of nanorod assemblies confined within liquid crystal

We study 4-n-octyl-4’-cyanobiphenyl (8CB) smectic (Sm) liquid crystal (LC) /nanorods (NRs) composite thin films. The aim is to obtain NR assemblies of controlled order and orientation, capable of inducing highly anisotropic optical properties. For gold NRs, the desired features are the optical plasmonic absorption of light but also the local exaltation of electromagnetic field, which both become sensitive to the incident light polarization if the NR assembly has high order and well-defined orientation (fig1c) [1, 2]. For fluorescent NRs the emission polarization is parallel to the NR’s long axis (fig1b), requiring a unique and well-defined NR orientation so as to reach macroscopic anisotropy [3,4]. We thus create oriented topological defects (TDs) in thin 8CB Sm films that confine NRs in their cores leading to original NR assemblies and related NR optical properties (fig1b-c).