Electric Field-Induced Optical Anisotropy of Model Rod-Like Colloids, Carbon Nanotubes

The high aspect ratio of carbon nanotubes exhibits a fundamental structural anisotropy that plays a critical role in various applications including nanoscale transistors, electrochemical electrodes, and flexible conductive films. In this work, we investigate the orientation of length/ chirality-sorted carbon nanotubes in aqueous suspensions by measuring the linear dichroism in response to high frequency electric fields. Based on the strong field-induced alignment with the nematic order parameter, the anisotropic polarizability of carbon nanotubes is determined and further compared to that of other high–aspect-ratio rod-like colloids.