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 $\mathrm{Li}\mathrm{Nb}{\mathrm{O}}_3$ 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 $\mathrm{Li}\mathrm{Ta}{\mathrm{O}}_3$ , the multiwalled carbon nanotubes align parallel to the wave vector due to negligible fluidic processes.