Properties of CNTs

PROPERTIES OF CNTs
Mechanical properties
(a) Carbon nanotubes are very strong and their elastic flexibility is indicated by young’s modulus. Young’s modulus of carbon nanotubes are 10 times than that of steel.
(b) CNTs withstand extreme strain and tension. Most of the materials fracture on bending because of the presence of more defects but CNTs possess only few defects in the structure.

Electrical properties
The electrical properties of CNTs vary between metallic to semiconducting materials. It depends on the diameter and chirality of the nanotubes. The very high electrical conductivity of CNTs is due to the minimum defects in the structure.

Thermal Conductivity
The thermal conductivity of CNTs is very high this is due to the vibration of covalent bonds. Its thermal conductivity is 10 time greater than the metal. The high thermal conductivity is due to minimum defects in the structure.

Vibrational properties
As in normal molecules the atoms in a CNT are continuously vibrating back and forth CNTs have two normal modes of vibration.
(i) A1g mode : It involves “ in and “out” oscillation.
(ii) E2g mode : It involves a squashing of the tube ( oscillation between sphere and an ellipse )
The frequencies of two modes of vibrations are Raman active.

Kinetic Properties
The inner tubes of MWNTs can slide without any friction within the outer nanotubes leading to an atomically perfect rotational bearing.