Organizing single-walled carbon nanotubes on gold using a wet chemical self-assembling technique

We provide a wet chemical approach for organizing randomly tangled single-w alled carbon nanotubes (SWCNTs) on gold surfaces. The as-grown nanotubes we re first chemically cut into short pipes and thiol-derivatized at the open ends. The ordered assembly of SWCNTs was made by their spontaneous chemical adsorption to gold via Au-S bonds. Tapping mode atomic force microscopy (A FM) images clearly show that the nanotubes have been organized on gold, for ming a self-assembled monolayer structure with a perpendicular orientation. The adsorption kinetics of the nanotubes was very slow in comparison to co nventional alkanethiols. The adsorption rate varied inversely with tube len gth. The nanotubes tend to form bundles as the adsorption propagates, follo wing a "nucleation adsorption mechanism". This work demonstrates that "gian t" carbon nanotubes can be assembled on Au surfaces using wet chemistry sim ilar to that exploited for "small" organic self-assembling species. We beli eve that assembled nanotube arrays will provide wide possibilities for appl ications.