Electrical polarizability of carbon nanotubes in liquid suspension

The alignment and polarizability of single-wall carbon nanotubes in dilute ethanol suspensions under low-frequency, alternating-current electric fields were investigated through optical polarimetry. The nematic order parameter was determined by measuring changes in the state of polarization of a laser beam transmitted through the sample. The dependence of the measured alignment on the electric field was found to be consistent with a thermal-equilibrium distribution of freely rotating, polarizable rods. The polarizability determined by fitting to this model is consistent with the classical result for a conducting ellipsoid of the dimensions of the nanotubes.