This document discusses carbon nanotubes (CNTs). CNTs were first discovered in 1991 and have a nanoscopic cylindrical structure. There are two main types: single-walled and multi-walled. CNTs can be synthesized through arc discharge, chemical vapor deposition, and laser ablation methods. CNTs have extraordinary mechanical and thermal properties, such as being 200 times stronger than steel but also excellent conductors of electricity and heat. Potential applications include use in bulletproof vests, water filters, and other future technologies. However, challenges remain around production mechanisms and skilled workforce development.

1. BY: INDRANEEL MAJUMDAR & ANJANI KUMAR
(5th SEMESTER, MECHANICAL ENGG,PCE RKL).

2.  Introduction
 Discovery
 Carbon Nanotubes (CNTs)
 Types
 Methods of synthesis
 Properties
 Applications
 Obstacles
 Conclusion
 Reference

4. Carbon nanotube (CNTS) were first discovered
in 1991 by the Japanese electron
microscopist Sumio Iijima who was studying
the material deposited on the cathode during
the arc-evaporation synthesis of fullerenes.

5.  Carbon nanotubes (CNTs) are carbon allotropes
 Its nanoscopic in structure and in the shape of a
hollow cylinder
 cylinders closed both ends by semi-fullerene
structures.
 diameter as small as 1nm
 can have one “layer” or wall (single walled
nanotube)
 more than one wall (multi walled nanotube).

6. Armchair (n,m) =
(5,5)
= 30
Zig Zag (n,m) =
(9,0)
= 0
Helical (n,m) =
(10,5)
0 < < 30

7.  Single walled  Multi walled

9.  Connect two
graphite rods to a
power supply, place
them millimeters
apart, and throw
switch. At 100 amps,
carbon vaporizes in
a hot plasma.
 Can produce SWNT
and MWNTs with few
structural defects
 Tubes tend to be
short with random
sizes and directions

10.  Place substrate in oven, heat to 600
C, and slowly add a carbon-bearing
gas such as methane. As gas
decomposes it frees up carbon
atoms, which recombine in the form
of CNTs
 Easiest to scale to industrial
production; long length

11.  Blast graphite with
intense laser pulses;
use the laser pulses
rather than electricity
to generate carbon
gas from which the
CNTs form; try various
conditions until hit on
one that produces
prodigious amounts of
SWNTs

12.  Extremely high Young’s modulus
 200x stronger than steel of the same
diameter
 The first synthetic material to have
greater strength than spider silk
 Excellent conductors of electricity and
heat

13. The strength of the
carbon-carbon bonds
gives carbon
nanotubes amazing
mechanical properties.
The Young's modulus of
the best nanotubes can
be as high as 1000 GPa
which is approximately
5x higher than steel.
The tensile strength, or
breaking strain of
nanotubes can be up to
63 GPa, around 50x
higher than steel.

14.  CNTs very good thermal
conductors along the tube,
exhibiting a property
known as "ballistic
conduction", but good
insulators laterally to the
tube axis. Measurements
show that a SWNT has a
room-temperature thermal
conductivity along its axis
of about 3500 W·m−1·K−1
compare this to copper, a
metal well known for its
good thermal conductivity,
which transmits 385
W·m−1·K−1.

15.  Because of the
symmetry and unique
electronic structure of
graphene, the structure
of a nanotube strongly
affects its electrical
properties. metallic
nanotubes can carry an
electric current density
of 4 × 109 A/cm2, which
is more than 1,000
times greater than
those of metals such
as copper.

16. ++++++
+
no
+++++
no
Conducts
electricity
++++++++++Buckyballs
++++++++++++++++Carbon
Nanotubes
+++Not known+++++Diamond
+++++++++Graphite
+++Coal
Conducts
heat
Tensile
strengthHardnessAllotrope

18. Water filters
Bullet proof vest

20.  Lack of vision to identify those aspects that
could be changed through its use.
 Lack of skilled personnel.
 Level of Investment.

21. Their mechanical properties, and unique
electronic properties make them both
interesting & useful in future
technologies, but growth mechanisms yet
to be fully established.

22.  http://www.ipt.arc.nasa.gov
 http://www.mknano.com
 www.nanohub.org
 www.wikipedia.com
 Carbon nanotubes science and
applications BY M.Meyyapan