Electromagnetic-Field-Induced Ring Formation in Single-Walled Carbon Nanotubes

We develop a continuum model to explain the ring formation observed in suspensions of carbon nanotubes (SWNTs) under electromagnetic field. The electromagnetic field induces a dipole moment in SWNTs which results in an axial compression in metallic nanotubes. Above a critical electric field intensity, the SWNTs buckle and form circular rings with the assist of van der Waals attraction between the ends of each nanotube. The kinetics of this process in controlled by bending energy (barrier) of the nanotubes and the electromagnetic field provides the necessary energy to overcome this barrier.