Carbon nanotube alignment by surface acoustic waves

We present a realization of carbon nanotube alignment. Surface acoustic waves are applied to a multiwalled carbon nanotube suspension and the lateral piezoelectric field of the standing wave aligns the carbon nanotubes with an angle of 25° to 45° on LiNbO3 with respect to the direction of wave propagation. This angle results from a superposition of the aligning electric field and a perpendicular fluidic flux in the carbon nanotube suspension caused by the energy transfer from the surface acoustic wave into the liquid. On LiTaO3, the multiwalled carbon nanotubes align parallel to the wave vector due to negligible fluidic processes.