What are Carbon Nanotubes? Essay

543 Words 3 Pages
Carbon nanotubes are long cylindrical structures of small nano-scale diameters formed only by
carbon atoms. These structures can be understood as rolled sheets of graphene into a tube. The
interactions between carbon atoms are mostly defined as Van der Waals forces.

If we categorize CNTs by their structure, the following division can be obtained:

- single-walled nanotubes (SWNTs)

- multi-walled nanotubes (MWNTs)

The above structures differ in the arrangement of graphene cylindrical structures . SWNTs have
only one single layer of graphene tubes, whereas MWNTs have many. There are three geometrical
types of nanotubes: armchair, zig-zag and chiral. Between these types there is a difference of how
the graphene is formed into a tube. The zig-zag (n, 0) has carbon-carbon bonds (C-C bonds)
parallel to the axis of the nanotube, while the armchair (n,n) has bonds perpendicular to the axis.
A chiral (n,m) nanotube has a spiral symmetry and the chiral angle is between 0° and 30°.
Carbon nanotubes are not only structures that have the simplest chemical composition and atomic
bonding configuration, but also, at the same time, these structures have amazing properties which
is the actual reason of them being studied. They have unparalleled electrical, mechanical and
optical properties and show great thermal and electrical conductivity on the level of other
conductive materials. Although they have negligible dimension, these structures are stronger than
any other…

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