Bending of multiwalled carbon nanotubes over gold lines

Abstract

We have investigated an experimentally moderate bending of multiwalled carbon nanotubes (MWNTs) in the perpendicular direction from flat substrates. The tubes were in the diameter range of 3–13nm and deposited over lithographically fabricated gold lines whose height determined the total bending. In our model for the bending profile we take into account the van der Waals attraction between the substrate and the MWNT and the opposing elastic bending force. With reasonable parameters for the competing forces we obtain an agreement between the model and the experimental data for the critical distance between two adjacent lines when the van der Waals attraction can no longer prevent elastic forces from straightening the tube to a suspended position between the lines. However, for the smallest nanotubes a simple classical model is clearly insufficient.