Scanning electron micrograph (SEM) of carbon nanotubes (single and multi-walled). Carbon nanotubes are rolled sheets of carbon atoms that form cylinders. They are structurally related to fullerenes; cages of carbon atoms discovered in 1985. The cylindrical carbon nanotubes can be either single-walled (SWNTs) or multi-walled (MWNTs). MWNTs have multiple carbon wall layers which do not change the nanotubes mechanical or electrical properties. Nanotubes are just a few nanometres in diameter and several microns long. The tiny size of the tubes may yield useful electrical components. Nanotubes have a very broad range of electronic, thermal, and structural properties that change depending on the different physical parameters of nanotubes. SWNTs and (MWNTs) can be formed to produce nanofibers and nanoelectronic components. Magnification: x13, 335 when shortest axis printed at 25 millimetres.