A non-contact strategy for controlled enrichment, manipulation, and separation of carbon nanotubes by surface acoustic waves

We report a flexible method to manipulate carbon nanotubes (CNTs) in a microfluidic device employing surface acoustic waves (SAWs). First, CNTs in suspension were enriched to the surface of the piezoelectric substrate by SAW; standing SAWs (SSAWs) could orchestrate controllable alignment and movement of the CNTs in a microfluidic channel. In the two-dimensional (2D) case, moreover, the enriched and aligned CNTs could be precisely rotated to all directions via adjusting the coupling of the 2D SSAWs. Finally, we demonstrated the SAW technique as a promising candidate for purifying metallic single-walled carbon nanotubes from the mixture species in a non-contact manner. (C) 2013 AIP Publishing LLC.