Watch them grow

A team of scientists led by Dr Stephan Hofmann from the Engineering Department at the University of Cambridge have successfully produced live video footage that shows how carbon nanotubes, more than 10,000 times smaller in diameter than a human hair, form.

They show nanofibres and nanotubes nucleating around miniscule particles of nickel and are already offering greater insight into how these microscopic structures self-assemble.

The two videos (for links see below) show how the nickel reacts a process called catalytic chemical vapour deposition (CVD). 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.