Carbon Nanotubes

Presented by
Ashesh Bansal
Guided By : Mr. Vipin Goyal
Department of Mechanical Engineering
Jaipur Engineering College And Research Centre , Jaipur
1

DISCOVERY …..
CNTs were discovered In 1991 by the
Japanese Electron Microscopist Sumio
Iijima Nec Laboratory in Tsukuba used
high-resolution Transmission Electron
Microscopy to observe carbon
nanotubes. Iijima's discovery of multi-
walled carbon nanotubes in 1991 and
Mintmire, Dunlap, and White's
independent prediction that if single-
walled carbon nanotubes could be
made, then they would exhibit
remarkable conducting properties

STRUCTURE
 CNTs are allotropes of carbon.
 Rolled- up graphene sheets.
 Graphene is an individual
graphite layer.
 The bonding in carbon
nanotubes is sp², with each
atom joined to three
neighbors, as in graphite.

 This bonding structure,
which is stronger than the
sp3 bonds found in diamond,
provides the molecules
with their unique strength.
 Under high pressure,
Nanotubes can merge
together, trading some
sp² bonds for sp³ bonds,
giving the possibility of
producing strong and
unlimited length wires
through high-pressure
nanotube linking.

CNTs (As per Wall structure)
Single walled Carbon
Nanotubes
 Single layer
 Bulk synthesis is difficult,
require proper control
 High defects
 Less pure Multi walled Carbon Nanotubes
 Multi layers
 Synthesis is easy
 Defects are less
 Very tough to remove defects

PROPERTIES OF CNTs
“Current-carrying capacity is 1000 times higher than that of
copper...” due to more electron than and metallic surface
Thermal stability and Reliability
CNT is thermal stable to 4000k.
Smart Sensors
Chemically active and highly sensitive

Mechanical Properties of Engineering Fibers
Fiber
Material
Specific
Density
E(TPa
)
Strength
(GPa)
Strain at
Break (%)
Carbon
Nanotubes
1.3-2 1 10-60 10
HS Steel 7.8 0.2 4.1 <10
Carbon
Fiber PAN
1.7-2 0.2-
0.6
1.7-5 0.3-2.4
Carbon
Fiber Pitch
2-2.2 0.4-
0.96
2.2-3.3 0.27-0.6
 The strongest and most
flexible molecular
material because of CC
covalent bonding and
hexagonal network
architecture.
 Strength to weight ratio
~500 times greater than
Al, steel, titanium.
 CNT is as hard as
diamond and its
thermal capacity is
twice that of pure
diamond

Material Thermal Conductivity (W/m.k) Electrical
Conductivity
Carbon Nanotubes >3000 10^6-10^7
Copper 400 6*10^7
Carbon Fiber – Pitch 1000 2-8.5*10^6
Carbon Fiber – PAN 8-105 6.5-14*10^6
 Electrical Properties:-
Symmetry and unique electronic structure of graphene, the
structure of a nanotube strongly affects its electrical
properties Very high current carrying capacity.
 Thermal Conductivity :-
Measurements show that a SWNT has a room-temperature
thermal conductivity more than copper.

SYNTHESIS OF CNTs
 Techniques have been developed to
produce nanotubes in sizeable quantities,
including
 Arc discharge
 Laser ablation
 Chemical vapor deposition (CVD).
 Most of these processes take place in
vacuum or with process gases. CVD growth
of CNTs can take place in vacuum or at
atmospheric pressure.
 SWNTs and MWNTs are usually made by
carbon-arc discharge, laser ablation of
carbon, or chemical vapor deposition
(typically on catalytic particle).

ARC DISCHARGE
 Two graphite electrodes are placed in inert
atmosphere.
 Current is passed, anode is consumed and material
forms on cathode.
LASER ABLATION
 A pulsed laser vaporize a graphite target in inert
atmosphere.
 Nanotubes develop on the cooler surface of the
reactor.
 Yielding is 70%.
CHEMICAL VAPOR DEPOSITION
 A substrate is prepared with a layer of metal catalyst
article.
 Heated up to 700°C
 Two gases are blend into the reactor e.g. Nitrogen
and a carbon containing gas

ADVANTAGES
 Extremely small and lightweight.
 Resources required to produce them are plentiful, and
many can be made with only a small amount of material.
 Are resistant to temperature changes, meaning they
function almost just as well in extreme cold as they do in
extreme heat.
 Improves conductive, mechanical, and flame barrier
properties of plastics and composites.
 Enables clean, bulk micromachining and assembly of
components

OBSTACLES
 Difficulty of mass production for industrial
purposes.
 Secondly is the solubility of CNTs in the
water.
 Despite all the research, scientists still
don't understand exactly how they work.
 Extremely small, so are difficult to work with.
 Currently, the process is relatively expensive
to produce the nanotubes.
 Would be expensive to implement this new
technology in and replace the older
technology in all the places that we could.

APPLICATIONS
Energy storage
 Lithium batteries
 Hydrogen storage
Paper battery
 Strong Wires than steel.
 Oscillators ,speeds of > 50 GHz.
 Alternatives to traditional electrical
actuators
 Could easily be mistaken for a sheet of black
paper

Solar storage
Reinforcement of armor and
other materials
SWNT films 90% transparency
Sheet resistivity of 100 ohmper
square
 PETN (PantaErythritol TetraNitrate)
can be ignited with a camera flash.

Future of CNTs
Production Capacity increasing
 Several producdts are already in the market, such as
racquets, golf clubs, surfboards, ice hockey sticks, mass
transportation fuel system components, battery electrode
additives, plastics additives and masterbatches.
 More than 100 companies are
manufacturing CNT
 The largest share of global CNTs
is accounted for by plastics and
composites with sales of $472.9
million in 2010

 carbon nanotubes account for a 28% market share of
overall nanomaterials demand. In terms of production
capacity
 The production capacity of CNTs has increased significantly
in the last five years
 Only about 25% of the global CNTs production capacity was
produced in 2010
 Average production at full capacity is estimated to be
about 40- 50% in 2016
 Companies Producers include Arkema , Nanocyl, Showa
Denko , SouthWest NanoTechnologies, Inc.,Thomas Swan
and many more.

CONCLUSION
 CNTs are nanometer-length shells of carbon.
 Possess a combination of unique physical and chemical
properties.
 Can be applied in a variety of fields.
 Exhibits incredible strength, elasticity, thermal electrical
conductivity.
 Pivotal element in Nano technology.
 Can be applied to a variety of fields.
 Technology is in its infancy and will take several years to
develop.

References
 Chapin, D.M., C.S. Fuller, G.L. Pearson, (1954), A New Silicon
P-N Junction Photocell for Converting Solar Radiation into
Electrical Power, Journal of Applied Physics, 25:676-677.
 Noguera, A.F., C. Longo, M.A. De Paoli, (2004), Polymers in
dye sensitized solar cell: overview and perspectives, Coord.
Chem. Rev. 248:1455.
 Jing-Zhi Chen, Yin-Chen Yan and Kuan-Jiuh Lin, Effects of
Carbon Nanotubes on Dye-Sensitized Solar Cells, Journal of
the Chinese Chemical Society, 2010, 57, 1180-1184.
 OngonTopon, Daisuke Matsumoto and Masayasu Inaguna,
Carbon Nanotubes Counter Electrode for Dye-Sensitized
Solar Cell, Fujikura Technical Review, 2011.
 Gratzel, M., ‘Dye-Sensitized Solar Cells’, L. Photochem.
Photobio. C: Photochem. Reviews 4, 2003, pp. 145-153.

THANK YOU
By:
Ashesh Bansal
Mechanical Engineering
3rd Year
JECRC, Jaipur
E.mail- bansalashesh@gmail.com

Carbon Nanotubes

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