Noncovalent Self-Assembly of Carbon Nanotubes for Construction of “Cages”

A hollow spherical cage made of nested single-walled carbon nanotubes is constructed using self-assembly techniques. Nanotubes are first adsorbed onto amine-terminated silica gels in solution. Then, the drying and readsorption cycle grow the nanotube nest layer-by-layer. Finally, silica gels are etched away to give hollow cages. The initial amine−nanotube interactions determine the nested network, and nanotube−nanotube interactions thicken each arm of the nest.