Class: Material Science EngineeringStudent : Hoang Van Tien Hanoi -2012
Nanomaterials  Top -down approaches  Bottom-up approaches  Functional approaches  Biomimetic approaches ...
Bottom up synthesis Solgel synthesis Precipitation Physical vapor synthesis Chemical vapor condensation Spray convers...
Chemical vapor condensation Chemical vapor deposition (CVD) synthesis is achieved by putting a carbon source in the gas ...
 Case study: preparation of carbon nano tube by chemical vapor condensation method. -plasma enhanced ...
the growth mechanism
process The energy source is used to "crack" the molecule into reactive atomic carbon. The carbon diffuses towards the ...
positional control onnanometre scale CVD carbon nanotube synthesis is essentially a two-step process : -catalyst prepar...
Thermal chemical vapor deposition a schematic diagram of thermal CVD apparatus in the synthesis of carbon nanotubes.
Catalytic growth Schematics of a CVD deposition ovenThis method is based on the decomposition of a hydrocarbon gas ...
Thermal chemical vapor deposition  Catalysts : Fe , Ni, Co …  Substrate : Si,SiO2,glass…  Gas flow : 40ml/min  t = 450...
product Advantages: -Typical yield: 20-100% - Long tubes with diameter ranging from 10-240 nm for MWNT (multi walled nano...
Laser-assisted thermalchemical vapour deposition
 Sources of laser:a medium power, continuous wave CO 2 laser,perpendicularonto a substrate, pyrolyses sensitised mixtu...
product The diameters of the SWNTs range from 0.7 to 2.5 nm. The diameter range of the MWNTs is 30 to 80 nm 43 ...
Purification The main impurities :graphite (wrapped up) sheets, amorphous carbon, metal catalyst and the smaller fuller...
applicationsNanotubes are rolled-up graphene sheets, and graphene isone of the stiffest materials when subjected to deform...
Schematics of a nanotube transistor, with some measurements.
Use of a MWNT as AFM tip. VGCF stands for Vapour Grown Carbon Fibre.At the centre of this fibre the MWNT forms the tip
sources1. D.A.Bochvar and E.G.Galpern, Dokl.Akad.Nauk.USSR, 209, (610, 1973 )2.http://www.ou.edu/engineering/nanotube, 2...
Nanomaterials present
Nanomaterials present
Nanomaterials present
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Nanomaterials present

Published on: Mar 3, 2016
Published in: Education      Technology      Business      
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Transcripts - Nanomaterials present

  • 1. Class: Material Science EngineeringStudent : Hoang Van Tien Hanoi -2012
  • 2. Nanomaterials  Top -down approaches  Bottom-up approaches  Functional approaches  Biomimetic approaches  Speculative
  • 3. Bottom up synthesis Solgel synthesis Precipitation Physical vapor synthesis Chemical vapor condensation Spray conversion processing
  • 4. Chemical vapor condensation Chemical vapor deposition (CVD) synthesis is achieved by putting a carbon source in the gas phase and using an energy source, such as a plasma or a resistively heated coil, to transfer energy to a gaseous carbon molecule. Types :plasma enhanced CVD, thermal chemical CVD, alcohol catalytic CVD, vapour phase growth, aero gel-supported CVD and laser-assisted CVD. -Gaseous carbon sources : methane, carbon monoxide and acetylene…
  • 5.  Case study: preparation of carbon nano tube by chemical vapor condensation method. -plasma enhanced CVD, -thermal chemical CVD, -alcohol catalytic CVD, -vapour phase growth, -aero gel-supported CVD -laser-assisted CVD.
  • 6. the growth mechanism
  • 7. process The energy source is used to "crack" the molecule into reactive atomic carbon. The carbon diffuses towards the substrate, which is heated and coated with a catalyst where it will bind. Carbon nanotubes will be formed if the proper parameters are maintained.
  • 8. positional control onnanometre scale CVD carbon nanotube synthesis is essentially a two-step process : -catalyst preparation -actual synthesis of the nanotube. The catalyst is generally prepared by sputtering a transition metal onto a substrate and then using either chemical etching or thermal annealing to induce catalyst particle nucleation. Thermal annealing results in cluster formation on the substrate, from which the nanotubes will grow.
  • 9. Thermal chemical vapor deposition a schematic diagram of thermal CVD apparatus in the synthesis of carbon nanotubes.
  • 10. Catalytic growth Schematics of a CVD deposition ovenThis method is based on the decomposition of a hydrocarbon gas over atransition metal to grow nanotubes in a chemical vapor deposition (CVD)reactor
  • 11. Thermal chemical vapor deposition  Catalysts : Fe , Ni, Co …  Substrate : Si,SiO2,glass…  Gas flow : 40ml/min  t = 450-1050 oC  The diameter range of the carbon nanotubes depends on the thickness of the catalytic film example : - By using a thickness of 13 nm, the diameter distribution lies between 30 and 40 nm. - By using a thickness of 27 nm is used, the diameter range is between 100 and 200 nm.
  • 12. product Advantages: -Typical yield: 20-100% - Long tubes with diameter ranging from 10-240 nm for MWNT (multi walled nanotubes) and 0.6-4 nm for SWNT( single walled nanotubes). - Easiest to scale up to industrial production; long length, simple process, SWNT diameter controllable, quite pure Disadvantages: - large diameter range =>>>poorly controlled. -often riddled with defects
  • 13. Laser-assisted thermalchemical vapour deposition
  • 14.  Sources of laser:a medium power, continuous wave CO 2 laser,perpendicularonto a substrate, pyrolyses sensitised mixtures of Fe(CO) 5 vapour and acetylene in a flow reactor. Catalyst: Fe (very small iron particles) Substrate: sillica. iron pentacarbonyl vapour, single- and multi- +ethylene walled carbon +acetylene nanotubes
  • 15. product The diameters of the SWNTs range from 0.7 to 2.5 nm. The diameter range of the MWNTs is 30 to 80 nm 43 prefer grow single rather than multi-walled nanotubes . Hight purity High power requirement
  • 16. Purification The main impurities :graphite (wrapped up) sheets, amorphous carbon, metal catalyst and the smaller fullerenes… Rules : -separate the SWNTs from the impurities - give a more homogeneous diameter or size distribution. The techniques that will be discussed are oxidation, acid treatment, annealing, ultrasonication, micro filtration, ferromagnetic separation, cutting, functionalisation and chromatography techniques.
  • 17. applicationsNanotubes are rolled-up graphene sheets, and graphene isone of the stiffest materials when subjected to deformationsparallel to the sheet.⇒nanotubes show exceptional mechanical properties,especially a high strength-to-weight ratio.Applications: Field emission Field emission Nanotube sensors Nanotube transistors Nanotubes as SPM tips….
  • 18. Schematics of a nanotube transistor, with some measurements.
  • 19. Use of a MWNT as AFM tip. VGCF stands for Vapour Grown Carbon Fibre.At the centre of this fibre the MWNT forms the tip
  • 20. sources1. D.A.Bochvar and E.G.Galpern, Dokl.Akad.Nauk.USSR, 209, (610, 1973 )2.http://www.ou.edu/engineering/nanotube, 20033. http://nanotube.msu.edu/4.http://www.pa.msu.edu/cmp/csc/nanotube.htm5 5.http://en.wikipedia.org/wiki/Carbon_nanotube 6. http://students.chem.tue.nl/carbonnanotubes/applica