Alice

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Alices Adventures in Nanotubeland!

• Nikta Fakhri

Chemical and Biomolecular Engineering Department
Illustration by Sir John Tenniel from Lewis
Carroll's Alice's Adventures in Wonderland (1865)
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OUTLINE

• What is a carbon nanotube (CNT)?
• What is a single-walled carbon nanotube (SWNT)?
• How to Produce SWNT?
• Why do we care (SWNT properties)?
• Potential application
• Dispersing SWNTs

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IT ALL STARTS WITH CARBON
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SINGLE-WALLED vs. MULTI-WALLED CNTs
Length on the order of microns ? L / D 1000
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SWNT ROLLED-UP SHEET OF GRAPHITE
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SOME GEOMETRY!
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WHAT IS CHIRALITY?

• Properties of nanotubes are determined by
  chirality
• Chiral numbers are noted by (n,m)
• n counts in the direction of a1 and m counts in
  the direction of a2

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WHAT IS CHIRALITY?
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NOT ALL SWNTs ARE CREATED EQUAL
n-m divisible by 3 metallic otherwise
semiconducting
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PRODUCING NANOTUBES
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PRODUCING NANOTUBES
High-Pressure Carbon Monoxide Deposition HIPCO
Mixture of length and chirality
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PRODUCING NANOTUBES
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SWNT PROPERTIES

• Exceptional mechanical strength
• Tensile strength gt 37 GPa
• (Steel 2 Gpa)
• Young modulus 0.62 1.25 TPa
• (Steel 0.3 Tpa)

• Low density 1.4 g/cm3
• (Steel 8 g/cm3, Aluminum 2.7 g/cm3)

• Electrical resistivity 1 mW cm
• (Copper 1.7 mW cm)

• Thermal conductivity 3000 W / m K
• (Diamond 2000 W / m K)

Review by Baughman et al., Science, 297, 787
(2002)
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SOME POTENTIAL APPLICATIONS

• High-performance, lightweight fibers
• Replace Kevlar (PPTA) Zylon (PBO)

• High thermal conductivity fibers
• Heat pipes for space applications

• Ballistic electrical conductors
• The Armchair Quantum Wire
• Nearly lossless power transmission over gt 1000
  km
• No cooling (unlike High Temp Superconductors)

• Conductive transparent sheets coatings

• Multifunctional fibers and materials
• The ultimate carbon material !!!

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SWNT ROADBLOCKS

• Biggest problems 1993 (discovery)-onward
• No availability of high-quality SWNTs (until
  1995)
• Very low availability of SWNTs (until 1998)

• Biggest problem 1998-onward
• How to assemble / process SWNTs into
  macroscopic
• objects (fibers, sheets, etc.)
• ? PROCESSING

In order to make fibers and sheets of CNTs we
have to process them in liquid phase
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PUTTING CARBON NANOTUBES TO USE
MAKING FILMS AND FIBERS
Liquid processing

• Carbon nanotubes are sticky! (direct result of
  van der Waals forces
• Dispersion of nanotubes is important if you want
  to work with them

Possible approaches ?

1. Wrapping the nanotube
2. Functionalization
3. Acids

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1. WRAPPING THE NANOTUBES

• Put the nanotubes in the wrapper solution
• Bombard them with sound waves to break the
  bundles (sonication)
• Drawbacks ???

PHYSICAL
Application making films, biomedicine
Islam et al. Nano Letters 3, 269-273 (2003)
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2. SIDE-WALL FUNCTIONALIZATION

• Covalently bond functional groups to the side
  walls
• Open the carbon bonds
• Attach a molecule to the open bond to perform a
  desired function disperse better!
• Drawbacks ???

Application biomedicine
CHEMICAL
www.sunysb.edu/chemistry/ faculty/swong.htm
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3. ACID
Application making fibers

• Acid protonates the side walls of carbon
  nanotubes
• A dense layer of sulfuric acid anions surrounds
  the individual nanotubes
• Drawbacks ???

Which method is better? Depends on application
Ericson et al., Science 2004?Vol. 305. no. 5689,
pp. 1447 - 1450
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IMPORTANT POINTS

• Carbon nanotubes are a class of materials
• Two main subclasses
• Multi-walled
• Single-walled

• Each subclass is not a chemical species
• Chirality (n,m) identifies the species

• Now (2008)
• Mixtures of chiralities
• Mixtures of lengths

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CONCLUSIONS

• Carbon nanotube has some work to do!!
• MWNTs when cost is important (bulk)
• SWNT for high-value applications
• Manufacturing is maturing
• Dispersion liquid processing under control
• Tailored to host material
• Tailored to applications

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CONCLUSIONS

• Nanotubeland plays by its own rules rules we
  have yet to understand fully!

Illustration by Sir John Tenniel from Lewis
Carroll's Alice's Adventures in Wonderland (1865)
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WE ARE ALMOST THERE NANO-RACQUETS

• Babolat Racquet
• Reinforced in the throat and the bottom half of
  the head with carbon nanotubes
• Net result increase in stiffness and power of
  the racquet without adding weight
• Price 199

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SWNT MODEL TO SCALE

• Worlds largest SWNT model
• (22 April 2005, Guinness world record)
• Model of a (5,5) SWNT
• 65,000 pieces
• 360 m long, 0.36 m wide
• about 80 builders
• over 1000 in attendance

SMALL is really BIG!!
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PROFESSOR SMALLEY PROFESSOR PASQUALI
Be a scientist, save the world!