The term ‘Nanotechnology’ is derived from the Greek word ‘nanos’ and ‘dwarf’ The prefix nano in the word ‘Nanotechnology’ mean billionth (1 x 10-9 m) The design, characterization, production and applications of structures, systems and devices by controlling size and shape at 10-9 m scale or the single –atomic level.
COMMON TERMS Nanoparticles: The size of the particles which ranges from 1-50 nm Nanomaterials: materials having size less than 100 nm atleast in one dimension Nanotube: Nanometer scale tube like structure Nano manufacturing: methods for producing nanostructures in reliable and commercially viable ways
HOW DO WE SEE NANO PARTICLES ? Scanning electron microscope andtransmission electron microscope are usedto see the Nanoparticles
Carbon nanotubes are allotropes ofcarbon with a nanostructure having alength-to-diameter ratio greater than10,00,000. when graphite sheets arerolled into a cylinder, their edges joinedand form carbon nanotubes i.e., carbonnanotubes are extended tubes of rolledgraphite sheets.
SINGLE WALLED NANOTUBES MULTI WALLED NANOTUBES
SINGLE WALLED NANOTUBES It consists of one tube of graphite. It is one atom thick having a diameter of 2 nm of a length of 100 x 10-6 m. Structure of single walled CNT ‘s are: Armchair structure Zig – zag structure Chiral structure
MULTI WALLED CARBON NANOTUBES It consists of multiple layers of graphiterolled in on themselves to form a tubeshape.
MANUFACTURE OF CNT PYROLYSIS LASER EVAPORATION CARBON ARC METHOD CHEMICAL VAPOUR DEPOSITION
PROPERTIES OF CARBON NANOTUBES Carbon nanotubes are very strong and highly flexible Cnt’s withstand extreme strain and tension It has very high electrical conductivity It has very high thermal conductivity CNT atoms are continously vibrating back and forth