Forming Carbon Nanotubes
A team of scientists, including researchers at Cambridge University, have successfully produced live video footage that shows how carbon nanotubes, more than 10,000 times smaller in diameter than a human hair, form. The video sequences show nanofibres and nanotubes nucleating around miniscule particles of nickel and are already offering greater insight into how these microscopic structures self-assemble.
These two videos show how the nickel reacts a process called catalytic chemical vapour deposition. This is one of several methods of producing nanotubes, and involves the application of a gas containing carbon (in this case acetylene) to minute crystalline droplets referred to as "catalyst islands" (the nickel).
In conditions appropriate to creating nano-fibres, the catalyst was squeezed upwards gradually as carbon formed around it. When the application of gas was reduced to create single-walled nanotubes, the carbon instead lifted off the catalyst to form a tubular structure.