Explain different types of carbon nanotubes and give its applications.
1.A carbon nanotube is a small cylindrical carbon structure made out of graphene. The tube comprises hexagonal structures.
2.There are many different types of carbon nanotubes, but they are normally categorized as either single-walled (SWNT) or multi-walled nanotubes (MWNT).
The different types of carbon nanotubes are :
Single-walled nanotubes (SWNT) :
(i)Single-walled nanotubes (SWNT) consists of a graphene sheet rolled on leading to a single cylinder.Two halves of a Fullerene molecule closes the structure at both ends.
(ii)They have diameters ranging from 1nm to 5nm and are usually well over 1 mm in length.
(iii)The length to diameter ratio is generally about 1000 so that they can be considered as nearly one-dimensional structures.
Multi-walled nanotubes (MWNT) :
(i)MWNT is arrangement of several coaxial tubes of graphene sheets forming a tube like structure.Each MWNT has from 2 to 50 such tubes.
(ii)The separation between neighbouring tubes is roughly about 0.34-0.36 mm.
(iii) They have inner diameters from 1.5 to 15 nm and outer diameters from 2.5 to 30 nm.They are usually over 1 mm in length
APPLICATIONS OF CNT:
1.Improving Structural Properties
2.Enhancing electrical and thermal conductivity
4.Electromagnetic interference (EMI) shielding
5.Construction of nanoscale electronic devices.
6.The electron emission concept of CNTs is used in developing a flat-panel display.