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Unit 3 Nanomaterials
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Fullerenes Discovery Description and Nomenclature Applications
Synthesis and Manufacturing
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Introduction to Fullerenes
Discovery of Buckminster Fullerene Smalley’s Apparatus C60 A new form of carbon Discovery of carbon nanotubes Properties of carbon nanotubes Applications of carbon nanotubes
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Smalley, Kroto and Curl Research in long carbon chain molecules observed in outer space. Discovered Buckminsterfullerene a new form of carbon shaped like a soccer ball1985. Received the noble prize in Chemistry in 1996 for the discovery of fullerenes.
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Smalley’s Apparatus Distribution of carbon clusters produced under various experimental conditions. a) Low helium density over graphite target at time of laser vaporization. b) High helium density over graphite target at time of laser vaporization. c) Same as b), but with addition of "integration cup" to increase time between vaporization and cluster analysis.
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A new form of carbon! Graphite Diamond Fullerenes
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Sumio Iijima Discovered the carbon nanotube in 1991.
"Helical microtubules of graphitic carbon", S. Iijima, Nature 354, 56 (1991) The carbon nanotube is like a sheet of graphite that has been rolled into a cylinder.
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Carbon Nanotubes at CVTC
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Structure of Carbon Nanotubes
Zig Zag Armchair
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Chiral This configuration can be thought of as in between Zig Zag and Armchair. When viewed from the end Chiral looks like a spiral.
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Multiwalled Carbon Nanotubes
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Carbon Nanotube Nomenclature
(0,0) (1,0) (2,0) (1,1) (2,1) The white circles indicate a metallic CNT The black circles indicate a semiconductor CNT
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nxn Single Walled Carbon Nanotubes
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Distortions may occur in the CNT structure.
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C60 Enclosing Other Atoms
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Properties of Carbon Nanotubes
100 times stronger than steel at 1/6 the weight. Can be conductors or semiconductors.
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Potential Applications of Carbon Nanotubes
Energy storage Field emission devices Transistors AFM tips Nanotweezers Composite materials Nano structures Potential for extremely strong light weight cables/space elevator Physical memory
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Nanotubes may be spun into yarn
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Peapod Nanotubes
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Applications of Carbon Nanotubes
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Energy Storage Hydrogen Storage Lithium intercalation
6.5% by weight is needed Some studies show CNTs can achieve this Lithium intercalation Electrochemical supercapacitors
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Molecular Electronics
Field emitters Transistors – CNTs are p-type. They can be doped with K to make them n-type. Nanotube RAM physical memory device Nanowires CNT wires could replace copper wires someday. They may be able to carry x the current of copper. RbCs2C60 is the highest temperature carbon based super conductor yet discovered Tc = 33 K
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Single Nanotube Properties
Electronic properties can be measured with STM. Raman spectroscopy can be used to identify nanotubes.
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Nanoprobes and Sensors
AFM & STM probe tips Nanotweezers CNTs enclosed in lipids have been proposed as a biosensor.
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Composite Materials Composite materials usually involve adding a material to a polymer such as plastic. CNTs added to plastic can result in a conductive plastic.
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Carbon Nanotube Field Emission Display
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Super strong cables The strength of carbon nanotubes have suggested that it may be possible to create a super strong and lightweight cable with them. Such a cable may be able to create a space elevator.
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Space Elevator
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Functionalized Nanotubes
Carbon nanotubes can react chemically with many different chemicals. Functionalizing CNTs give them different properties such as they can be made soluble in water. Aldrich sells CNTs with polyaminobenzene sulfonic acid (PABS) a water soluble conducting polymer covalently bonded directly to the nanotube. Lipids can be organized around CNTs. Benzene can be attached to carbon nanotubes. Nanotubes can be opened filled with a metal and closed.
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Nano Machines
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CNT Synthesis A metal particle is acts as a catalyst for carbon nanotube growth. Growth takes place in an inert atmosphere. Often He. A source of carbon and energy are needed. Metal CH2=CH2 Metal Substrate Substrate
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Arc Discharge
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Arch discharge in LN2
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Laser Ablation
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Chemical Vapor Deposition (CVD)
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CNT Purification Carbon nanotubes must usually be purified in some way to remove the catalyst. Oxidation Acid treatment Annealing Ultrasound Magnetic purification Micro-filtration Chromatography
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Links Manufacturers:
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Manufacturers http://home.flash.net/~buckyusa/ http://carbolex.com/
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News http://www.newscientist.com/article.ns?id=dn7081
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