What Is Carbon nanotube?
A carbon nanotube is a cylindrical nanostructure made from a rolled sheet of carbon atoms arranged in a hexagonal lattice. Its diameter is often only a few nanometers, while its length can be thousands of times larger. A useful geometric relation is d = 2r, where diameter sets the scale for confinement, transport, and surface interaction. The same carbon bonding that gives graphene high strength also gives nanotubes unusual mechanical, electrical, and thermal properties.
In real systems, carbon nanotubes behave differently depending on their diameter, wall count, chirality, alignment, and surrounding material. They can act as conductors, semiconductors, reinforcement fibers, heat pathways, or molecular-scale channels. In nanofluidic membrane engineering, their narrow interiors can guide molecules through spaces where surface forces and quantum effects become significant.
The concept matters because carbon nanotubes turn atomic structure into useful device behavior. Their high aspect ratio and ordered carbon network make them valuable in composites, sensors, membranes, electrodes, and nanoscale electronics under practical loads.
Used in devices include field-effect transistors, conductive composites, scanning probe tips, gas sensors, and high-selectivity membranes that rely on nanoscale channels.
Example:
In a water purification membrane, aligned carbon nanotubes can form narrow channels that pass small molecules while rejecting larger or strongly interacting contaminants.
Related Terms:
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