Nanotechnology can be expressed as science and technology
where dimensions and tolerances in the range of 0.1 nanometer (nm) to 100 nm
play a critical role. Nanotechnology involves detailed engineering works in
the areas of 1) Nanomechanical engineering (the study of molecular machines) 2)
Nanoelectrical engineering (it involves nanometer scale electronic systems) 3)
complex systems like the assemblers, replicators and nano computers (To
manufacture a desired material with precise atomic placement).
Carbon Nano Tube
One of the important materials that were developed in nano
materials is carbon nano tube. Carbon nanotubes were discovered in 1991 as a
minor by-product of fullerene synthesis. It is a dichotomy that Carbon nanotubes being the
smallest of all tubes are strongest and stiffest materials on earth, they also
have a very high surface area to volume ratio. This strength results from the
covalent sp bonds formed between the individual carbon atoms. Multi-walled
carbon nanotube was tested to have a tensile strength of 63 gigapascals (GPa).
(This, for illustration, translates into ability to endure weight of 6300 kg on a cable with cross-section of 1 mm2.) Since carbon nanotubes have a
low density for a solid of 1.3-1.4 gcm−3, [17]
its specific
strength of up to 48,000 kNmkg−1 is the best
of known materials, compared to high-carbon steel's 154 kNmkg−1.
Under excessive tensile strain, the tubes will
undergo plastic deformation,
which means the deformation is permanent. This deformation begins at strains of
approximately 5% and can increase the maximum strain the tube undergoes before
fracture by releasing strain energy.
CNTs are not nearly as strong under compression.
Because of their hollow structure and high aspect ratio, they tend to undergo buckling when placed
under compressive, torsion or bending stress.
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The
author is CEO of
Namo Textile Co. Pvt. Ltd
