The sheet can be rolled up into small or large diameter nanotubes. However, because ultimately the tubes are made of individual atoms, the diameter has to reflect the exact number of atoms around the tube, and so only certain values of the diameter are allowed. Also, the spiral pattern of the atoms along the tube (like a barber shop pole) can be tight or loose.  Both the diameter and the spiral pattern are related to the way in which the graphene sheet is rolled up.

Like us on Facebook