Carbon nanotube pellet. Carbon nanotubes are one atom thick sheets of graphite, called graphene, rolled into cylindrical form with a diameter of the order of a nanometre. Nanotubes can be arranged concentrically into multi-walled nanotubes (MWNTs). The MWNT pellets seen here have been manufactured to be added to thermoplastics, to change the electrical and thermal properties and increase mechanical strength of the final material. Photographed at the Arkema Laboratory Pilot in Lacq, France, where MWNTs