New moves

Fullerenes inserted inside carbon nanotubes have been fused together to form chains that exhibit interesting rotational and translational motion

Credit: © 2008 ACS

Confinement of molecules inside carbon nanotubes has been shown to modify the chemical reactivity and dynamics of the encapsulated species, as well as the electronic transport and mechanical properties of the nanotubes themselves. Various fullerene molecules have been inserted into nanotubes to form peapod structures, but now researchers have fused together different types of fullerenes inside the peapod to create large chains.

Jamie Warner and colleagues¹ at Oxford University and Nagaoya University used transmission electron microscopy to induce coalescence of fullerenes and to study their movement. They inserted C₆₀ molecules into a single-walled carbon nanotube and then applied an electron beam that was high enough to distort the fullerenes, but not so high as to damage the nanotube. A large C₃₀₀ chain was formed, which exhibited translational motion along the nanotube and also a unique corkscrew rotation. Moreover, by inserting a mixture of C₆₀ and scandium-encapsulated C₈₂ molecules, large chains of mixed fullerenes were formed, which had a zigzag-shaped structure. The rotational motion of these resulted in expansion and contraction of the nanotube diameter.

These peapod structures could prove useful in nanodevices as they have potential as nanoactuators and can be controlled remotely by an electron beam.