Carbon Nanotubes; Brief Description; Synthesis procedures; Properties; Geometry; Applications;Future possibilities

1. CARBON NANO TUBES 1

2. Outline :
• Allotropes of carbon
with a cylindrical
structure
• Can be capped on the
ends with buckyballs
or open ended
• Composed entirely of
sp2 bonds
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3. Family Background (Hierarchy)
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4. CARBON NANO TUBES 4

5. Geometry
 Rollup Vector
 (n,m)
 n-m=3k
 Chiral Angle
 tan(θ) =
√3m/(2√(n2+m2+
nm))
 Arm Chair (n,n),
θ=90 ○
 Zig-zag (n,0),
θ=0 ○
 Chiral, 0○< θ<90 ○
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6. Geometry….
•N-m=3k CARBON NANO TUBES 6

7. CARBON NANO TUBES 7

8. Four Ways to Synthesize
Carbon Nanotubes
 Arc Discharge
 Laser Ablation
 Chemical Vapor
Deposition
(CVD)
 Ball Milling
http://students.chem.tue.nl/ifp03/synt
hesis.html

9. Chemical Vapor Deposition
 Carbon is in the gas
phase
 Energy source transfers
energy to carbon
molecule
 Common Carbon Gases
 Methane
 Carbon monoxide
 Acetylene (C2H2)
http://neurophilosophy.files.wordpress.com/2006/08/multiw
all-large.jpg

10. Chemical Vapor Deposition
 Carbon is in the gas phase
 Energy source transfers
energy to carbon molecule
 Usually a silicon plate
coated with iron particles is
the substrate.
 Common Carbon Gases
 Methane
 Carbon monoxide
 Acetylene

11. Chemical Vapor Deposition
 After energy transfer, the
carbon molecule binds to
the substrate
 Temperature between
~1300⁰F
 Carbon nanotubes stick to
each other due to Vander
walls force.
 When tubes are extracted
, cling on to each other
and pull each other out of
substrate
 Yield is usually about 30%
 One of the most common
methods of carbon
nanotube synthesis

12. Chemical Vapor Deposition
Advantages
 Easy to increase
scale to industrial
production
 Large length
 Simple to perform
 Pure product
Disadvantages
http://endomoribu.shinshu-u.
ac.jp/research/cnt/images/cat_cnt.jpg
• Defects are common

13.  Unique properties
 Material of the future
 Seemingly infinite
applications
 Possible health issues
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14.  Carbon nanotubes have the strongest tensile
strength of any material known.
 It also has the highest modulus of elasticity.
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Material
Young's
Modulus (TPa)
Tensile
Strength (GPa)
Elongation at
Break (%)
SWNT
~1 (from 1 to
5)
13-53E 16
Armchair
SWNT
0.94T 126.2T 23.1
Zigzag SWNT 0.94T 94.5T 15.6-17.5
Chiral SWNT 0.92
MWNT 0.8-0.9E 150
Stainless Steel ~0.2 ~0.65-1 15-50
Kevlar ~0.15 ~3.5 ~2
KevlarT 0.25 29.6

15. Stress-strain response of a CNT
under tensile loading
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16. Nanotubes: how they conduct
 In theory, metallic nanotubes can carry an electrical current density of 4×109 A/cm2
 Attach metal electrodes
 Can be connected to single tube or bundle of several hundred tubes
 Drop tubes onto electrodes (a)
 Deposit tubes on substrate, locate with scanning electron microscope, attach leads to
tubes using lithography (b)
 Advanced techniques
 Growing tubes between electrodes
 Attaching tubes to surface in controllable fashion using electrostatic or chemical forces.
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17. Coating and Films
 CNT-based transparent conducting films
 Alternative to expensive indium tin oxide (ITO)
 Flexible, and not brittle
 Application in
 Displays
 Touch screen devices
 photovolatics
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18. Coating ,Transparent conductors and
Films
 CNT conductors can be deposited from solution
 Slot-die coating
 Ultrasonic spraying
 Can be patterned by economic nonlithographic methods
 Recent developments have allowed for
 SWNT films with 90% transparency
 Sheet resistivity of 100 ohm per square
 Adequate applications such as CNT thin-film heaters like defrosting
windows or sidewalks
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19. Energy Storage
(supercapacitors)
 Study on packaged cells utilizing forest-grown
SWNTs revealed remarkable
performance
 16 Wh kg-1 energy density
 10 kW kg-1 power density
 16 year lifetime forecast
 The only drawback is the high cost of
SWNTs
 FUTURE WORK –
Super conductors
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20. Future Works
o Future Electrical
Transmission.
o Will cut the cost of Silver
required.
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21. SEM image of the smallest working
gear(CNT+nylon)
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22. The Space Elevator
• The Idea
– To create a tether from earth to some
object in a geosynchronous orbit. Objects
can then crawl up the tether into space.
– Saves time and money
• The Problem
– 62,000-miles (100,000-kilometers)
– 20+ tons
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23. The Space Elevator
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24. Hybrid Power Generation
o Charging your electric car within seconds using devices made of
carbon nanotubes!!!!
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25. More applications….
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26. Toxicity
 Research has
shown :-
 In rodents, carbon
nanotubes have
been found to
cause several lung
issues.
 The needle-like
shape of the fibers
is similar to that of
asbestos.
http://www.phy.mtu.edu/newsletter/research/FatNanotubes.jpg

27. In Conclusion…
 There are many unique properties
 Inhaling can cause toxic-reaction
 There are many ways to synthesize
 There are many exciting applications of
carbon nanotubes

28. In Conclusion…
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29. Sources
 M. S. DRESSELHAUS, G. DRESSELHAUS, and R. SAITO.
Carbon 33, 7 (1995)
 R. Martel, T. Schmidt, H. R. Shea, T. Hertel, and Ph.
Avourisa. App. Phys. Lett. 73, 17 (1998)
 Sander J. Tans, Michel H. Devoret et al. Nature 386,
474-477 (1997)
 Jean-Paul Salvetat et al. Phys. Rev. Lett. 82, 5 (1999)
 MICHAEL S. ARNOLD et al. Nature Nanotechnology 1,
60-65 (2006)
 www.noritake-elec.com/.../nano/structu.gif
 academic.pgcc.edu/~ssinex/nanotubes/graphene.gif
 nano.gtri.gatech.edu/Images/MISC/figure4.gif
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30. for bearing our presentation… 
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