Researchers from Shinshu University, CNRI Corporation, Japan and Massachusetts Institute of Technology have made the smallest free-standing single-walled carbon nanotube to date. The tube is around 0.43 nm in diameter and was produced using a floating-reactant method.
The procedure for making small nanotubes normally utilises confinement in a template like porous material or the centre of a multiwalled nanotube. In this case researchers used a nanozeolite floating-reactant chemical vapour deposition method. Here the zeolite powder provides a nanotube template by limiting the size of the catalytic iron particles. The zeolite is also a support for the catalyst and a floating substrate.