Synthesis of nanotubesSynthesis of nanotubesSynthesis of nanotubes

Ewelina BrodaEwelina BrodaEwelina Broda

Presentation Overview

1. Introduction2. History3. Types and structures4. Properties5. Synthesis6. Applications7. References

Allotropes of Elemental Carbon

History

1985 Discoverey of the buckyball (C60) and other fullerenesR. E. Smalley (Nobel Prize winning in 1996)

1991 Discovery of multi-wall carbon nanotubesS. Iijima

1992 Conductivity of carbon nanotubesJ. W. Mintmire, B. I. Dunlap and C. T. White

1993 Structural rigidity of carbon nanotubesG. Overney, W. Zhong, and D. Tománek

1993 Synthesis of single-wall nanotubesS. Iijima and T. Ichihashi

1995 Nanotubes as field emitters A.G. Rinzler, J.H. Hafner, P. Nikolaev, L. Lou, S.G. Kim, D. Tománek, P. Nordlander, D.T. Colbert, and R.E. Smalley

1997 Hydrogen storage in nanotubesA. C. Dillon, K. M. Jones, T. A. Bekkendahl, C. H. Kiang, D. S. Bethune and M. J. Heben

1998 Synthesis of nanotube peapodsB.W. Smith, M. Monthioux, and D.E. Luzzi

2000 Thermal conductivity of nanotubes S. Berber, Y.K. Kwon, D. Tománek

2001 Integration of carbon nanotubes for logic circuitsP.C. Collins, M.S. Arnold, and P. Avouris

2001 Intrinsic superconductivity of carbon nanotubesM. Kociak, A. Yu. Kasumov, S. Guéron, B. Reulet, I. I. Khodos, Yu. B. Gorbatov, V. T. Volkov, L. Vaccarini, and H. Bouchiat

Classification

Non carbon nanotubesMX2 compounds (M=transition metal; X= chalogen), eg.: WS2 and MoS2;BxCyNz, eg.: BN, BC3 and BC2N

Carbon nanotubes

Classification

Multi - walled nanotubesSingle - walled nanotubes

Multi – Walled Nanotubes

Russian dollmodel

Parchmentmodel

Single – Walled Nanotubes

Graphene Types of SWNTCarbon Nanotube Mr. Anurak Udomvech

Construction of Nanotubes

a1 , a2 primitive lattice vectors of graphene

Chiral vector: Ch = n1 a1 + n2 a2 n1 , n2 integers: chiral numbers

T tube axis

Mirror lines: "zig-zag line” through the midpoint of bonds"armchair line” through the atoms

θ - chiral angle

Sixfold symmetry: 0 ≤ θ < 60°http://en.wikipedia.org/wiki/Carbon_nanotubes

Armchair(n,n)

Zigzag(n,0)

Chiral(n,m)

http://en.wikipedia.org/wiki/Carbon_nanotubes

Properties

• Extraordinary electric properties• Very high tensile strength • Highly flexible – can be bent considerably without damage• Very elastic ~18% elongation to failure• Twice the thermal conductivity of diamonds• Low thermal expansion coefficient• Good electron field emitters• High aspect ratio (length = ~1000 x diameter)• Reported to be thermally stable in a vacuum up to 2800 deg. Centigrade (and we fret over CPU temps over 50o C)

Properties

• Electrical conductivity

Properties

http://nanopedia.case.edu/NWPage.php?page=nanotube.strength

Synthesis

1.) Arc discharge2.) Laser ablation3.) Chemical vapor deposition (CVD)

Techniques differ in:Type of nanotubes (SWNT / MWNT )Catalyst usedYieldPurity

Growth Mechanism

Arc Discharge

Arc Discharge

Electrodes are composed of high purity graphite (>99.999%)~70 A at ~18 V DC is applied to the electrodesCarbon nanotubes are formed at atmospheric pressures from the electrodes

Information courtesy of: K. Anazawa, K. Shimotani, C. Manabe, H. Watanabe, and M. Shimizu. “High-purity…magnetic field”

Laser Ablation

Laser Ablation

A well mixed acetylene-air mixture is burned inside a tube furnaceA laser is used to vaporize a metal target (either Fe or Ni)The post-flame exhaust gas is mixed with the metallic vapor and allowed to coolDuring cooling, carbon nanotubes are formed

Chemical Vapor Deposition (CVD)

Chemical Vapor Deposition (CVD)

Source of carbon atoms usually comes from an organic compound

Mixed with a metal catalyst and inert gas

Atomized and sprayed into reactor with temperatures ranging from 600ºC to 1200ºC

Pyrolysis of organic compound deposits carbon (as soot) and carbon nanotubes on reactor wall (usually a tube constructed from quartz)

Sources of Carbon

Typical Organic/Catalyst MixturesXylene/ferrocene (Andrews et al.)Toluene, benzene, xylene, mesitylene, and n-hexane/ferrocene (Vivekchand et al.)Ethylene and ethanol/Fe, Co, and Mo alloys (K. Mizuno et al.)

Typical Carrier GasesArgonHydrogen

Purification

Contaminants:Catalyst particlesCarbon clustersSmaller fullerenes: C60 / C70

Impossibilities:Completely retain nanotube structureSingle-step purification

Only possible on very small scale:Isolation of either semi-conducting SWNTs

Purification: Techniques

Removal of catalyst:Acidic treatment (+ sonication)Thermal oxidationMagnetic separation (Fe)

Removal of small fullerenesMicro filtrationExtraction with CS2

Removal of other carbonaceous impuritiesThermal oxidationSelective functionalisation of nanotubesAnnealing

Synthesis

The Wondrous World of Carbon Nanotubes Eindhoven University of Technology

Applications

Carbon Nano-tubes are extending our ability to fabricate devices such as:Molecular probesPipesWiresBearings SpringsGearsPumps

Applications

Molecular transistors.Field emitters.Building blocks for bottom-up electronics.Smaller, lighter weight components for next generation spacecraft.

Possible Applications of CNTs

Thank You for Your Attention!

References

http://www.pa.msu.edu/cmp/csc/nanotube.htmlhttp://www.photon.t.u-tokyo.ac.jp/~maruyama/nanotube.htmlCarbon Nano-tubes: An Overview An Undergraduate Research Paper By Scott E. Wadley http://students.chem.tue.nl/ifp03/Steffen Weber's Crystallography Picture Book Nanotubes & Nanocones Structure and Properties of Carbon Nanotubes Jannik Meyerhttp://en.wikipedia.org/wiki/Carbon_nanotubesR. Andrews, D. Jacques, D. Quan, and T. Rantell. “Multiwall Carbon Nanotubes: Synthesis and Application.” Accounts of Chemical Research. Vol. 35, No. 12, 2002A. Zettl “Non-Carbon Nanotubes” Advanced Materials Vol. 8, No. 5, 1996S.R.C. Vivekchand, L.M. Cele, F.L. Deepak, A.R. Raju, and A. Govindaraj. “Carbon nanotubes by nebulized spray pyrolysis.” Chemical Physics Letters. 386 (2004) 313-318