Changes
/* Types */
=== Types ===
[[Image:swcnt.jpg|right|200 px|thumb|Vectors representing orientation of three types of Single-walled CNT's]]
[[Image:dwcnt.jpg|right|200 px|thumb|A Double-walled CNT formed by multiple Single-walled CNTs]]
# '''[http://www.pa.msu.edu/cmp/csc/ntproperties/equilibriumstructure.html Single-walled CNT's]''': This type of nanotube can be formed by rolling Graphene sheet. Graphene is a single planar sheet of sp²-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. Types of Single-walled CNT's:
#* Zig-zag(n,0)
#* Armchair(n,n)
#* Chiral(2n,n)
# '''[http://www.nanotech-now.com/nanotube-buckyball-sites.htm Multi-walled]''': Multi-walled nanotubes(MWNT) consist of multiple layers of graphite rolled in on themselves to form a tube shape.
# '''[http://en.wikipedia.org/wiki/Fullerene Fullerite]''': Fullerites are the solid-state manifestation of fullerenes and related compounds and materials. Being highly incompressible nanotube forms, polymerized single-walled nanotubes (P-SWNT) are a class of fullerites and are comparable to diamond in terms of hardness.
# '''[http://en.wikipedia.org/wiki/Torus Torus]''': A nanotorus is a theoretically described carbon nanotube bent into a torus (doughnut shape).
# '''[http://en.wikipedia.org/wiki/Carbon_nanobud Nanobud]''': The material fullerene-like "buds" are covalently bonded to the outer sidewalls of the underlying carbon nanotube. This hybrid material has useful properties of both fullerenes and carbon nanotubes.
=== Properties ===
::* '''Physical Properties'''
{|border="2" cellspacing="0" cellpadding="4" width="65%"
|align = "center" bgcolor = "#D9D9D9"|'''Material'''
|align = "center" bgcolor = "#D9D9D9"|'''Young<nowiki>’</nowiki>s modulus''' (GPa)
|align = "center" bgcolor = "#D9D9D9"|'''Tensile Strength''' (GPa)
|align = "center" bgcolor = "#D9D9D9"|'''Density''' (g/cm3)
|-
|align = "center"|Single wall nanotube
|align = "center"|1054
|align = "center"|150
|align = "center"|N/A
|-
|align = "center"|Multi wall nanotube
|align = "center"|1200
|align = "center"|150
|align = "center"|2.6
|-
|align = "center"|Steel
|align = "center"|208
|align = "center"|0.4
|align = "center"|7.8
|-
|align = "center"|Epoxy
|align = "center"|3.5
|align = "center"|0.005
|align = "center"|1.25
|-
|align = "center"|Wood
|align = "center"|16
|align = "center"|0.008
|align = "center"|0.6
|-
|}
[http://www.applied-nanotech.com/cntproperties.htm Source link]
::* '''Electrical Properties''': Because of the symmetry and unique electronic structure of graphene, the structure of a nanotube strongly affects its electrical properties. For a given (n,m) nanotube, if n − m is a multiple of 3, then the nanotube is metallic, otherwise the nanotube is a semiconductor. Thus all armchair (n=m) nanotubes are metallic, and nanotubes (5,0), (6,4), (9,1), etc. are semiconducting. In theory, metallic nanotubes can have an electrical current density more than 1,000 times greater than metals such as silver and copper.
=== Method of fabrication ===
::* '''[http://nanotube.msu.edu/synthesis/ca.html Arc discharge]''': It is the simplest and most commonly used method of producing Carbon nanotubes. This method creates CNTs through arc-vaporization of two carbon rods placed end to end, separated by approximately 1mm, in an enclosure that is usually filled with inert gas (helium, argon) at low pressure (between 50 and 700 mbar).
::* '''[http://www.azonano.com/Details.asp?ArticleID=1561 Laser ablation]''': In 1996, a dual-pulsed laser vaporization technique was developed, which produced SWNTs in gram quantities and yields of >70wt% purity. Samples were prepared by laser vaporization of graphite rods with a 50:50 catalyst mixture of Co and Ni (particle size ~1um) at 1200oC in flowing argon, followed by heat treatment in a vacuum at 1000oC to remove the C60 and other fullerenes.
::* '''[http://en.wikipedia.org/wiki/Chemical_vapor_deposition Chemical vapor deposition (CVD)]''':Large amounts of CNTs can be formed by catalytic CVD of acetylene over Co and Fe catalysts supported on silica or zeolite.
== Application of Carbon nanotubes ==
::* '''Polymer Composites''': The first realized major commercial application of MWNTs is their use as electrically conducting components in polymer composites.Depending on the polymer matrix, conductivities of 0.01 to 0.1 S/cm can be obtained for 5% loading; much lower conductivity levels suffice for dissipating electrostatic charge. The low loading levels and the nanofiber morphology of the MWNTs allow electronic conductivity to be achieved while avoiding or minimizing degradation of other performance aspects, such as mechanical properties and the low melt flow viscosity needed for thin-wall molding applications.
::* '''Electrochemical devices''': Because of the high electrochemically accessible surface area of porous nanotube arrays, combined with their high electronic conductivity and useful mechanical properties, these materials are attractive as electrodes for devices that use electrochemical double-layer charge injection.
::* '''Hydrogen storage''': Nanotubes have been long heralded as potentially useful for hydrogen storage (for example, for fuel cells that power electric vehicles or laptop computers).
::* '''Field emission devices''': Industrial and academic research activity on electronic devices has focused principally on using SWNTs and MWNTs as field emission electron sources for flat panel displays, lamps, gas discharge tubes providing surge protection, and x-ray and microwave generators.
::* '''Nanometer-sized electronic devices''':
::* '''Sensors and probes''': Possible chemical sensor applications of nonmetallic nanotubes are interesting, because nanotube electronic transport and thermopower (voltages between junctions caused by interjunction temperature differences) are very sensitive to substances that affect the amount of injected charge.The main advantages are the minute size of the nanotube sensing element and the correspondingly small amount of material required for a response.
[http://www.eikos.com/articles/carbnano_routetoapp.pdf Source link]
[[Image:Carbon Nanotube1.jpg|700 px|center|thumb|Map categorization for CNT]]
== Top ongoing projects on CNT's ==
::* The Ajayan group is using carbon nanotubes as templates and molds for fabricating nanowires, composites, and novel ceramic fibers.[http://www.rpi.edu/locker/38/001238/INDEX.HTM]
::* Dai group discovered how to grow nanotubes in specific directions and orientations on substrates using a chemical vapor deposition process.[http://www.stanford.edu/dept/chemistry/faculty/dai/group/]
::* Smalley group is developing methods of production, purification, derivitization, analysis, and assembly of nanotubes to solve real world problems. [http://smalley.rice.edu/]
::* Sun Research group is researching on polymeric nanocomposite materials based on carbon nanotubes and semiconductor and metal nanoparticles. [http://www.ces.clemson.edu/lemt/research.htm]
::* Accelerator Laboratory, the University of Helsinki is researching on Ion irradiation as a tool for studying and modifying properties of carbon nanotubes.[http://beam.acclab.helsinki.fi/nanotubes/]
== IP Activity on carbon nanotubes ==
* Number of patents filled on nanotubes are increasing exponentially by years.
* Last year i.e 2007, around 1450 patents are filled in this field.
[[Image:report11.jpg|700px|center|thumb|IP Activity by year]]
* Major IPC classes with description is given.
[[Image:report3.jpg|700px|center|thumb|Top IPC]]
{|border="2" cellspacing="0" cellpadding="4" width="100%"
|align = "center" bgcolor = "#C0C0C0"|S. no.
|align = "center" bgcolor = "#C0C0C0"|IPC Classification
|align = "center" bgcolor = "#C0C0C0"|Description
|-
|align = "center"|1
|align = "center"|H01J
|align = "center"|ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
|-
|align = "center"|2
|align = "center"|C01B
|align = "center"|NON-METALLIC ELEMENTS AND THEIR COMPOUNDS
|-
|align = "center"|3
|align = "center"|H01L
|align = "center"|SEMICONDUCTOR DEVICES AND ELECTRIC SOLID STATE DEVICES
|-
|align = "center"|4
|align = "center"|B82B
|align = "center"|NANOTECHNOLOGY
|-
|align = "center"|5
|align = "center"|H01M
|align = "center"|BATTERIES OR FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
|-
|align = "center"|6
|align = "center"|B01J
|align = "center"|CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY AND THEIR RELEVANT APPARATUS
|-
|align = "center"|7
|align = "center"|D01F
|align = "center"|CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES, OR RIBBONS AND APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
|-
|align = "center"|8
|align = "center"|G01N
|align = "center"|INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
|-
|align = "center"|9
|align = "center"|B32B
|align = "center"|LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
|-
|align = "center"|10
|align = "center"|C08K
|align = "center"|USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES AS COMPOUNDING INGREDIENTS
|-
|}
* Hon Hai Prec Ind Co leads the number of patent filing by a great margin with their competitors.
* Samsung Electronics and Samsung SDI Co. Ltd. together contributes 148 patents.
[[Image:report4.jpg|700px|center|thumb|Top Assignee]]
== Sample Analysis ==
