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Carbon Nanotubes

Carbon Nanotubes

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.com

AVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

1Averzs Technologies

General FactGraphite vs. DiamondsWhat's the difference between graphite and diamonds? Both materials are made of carbon, but both have vastly different properties. Graphite is soft; diamonds are hard. Graphite conducts electricity, but diamonds are insulators and can't conduct electricity. Graphite is opaque; diamonds are usually transparent. Graphite and diamonds have these properties because of the way the carbon atoms bond together at the nanoscale. T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

A carbon nanotube is a Nano-size cylinder of carbon atoms. Imagine a sheet of carbon atoms, which would look like a sheet of hexagons. If you roll that sheet into a tube, you'd have a carbon nanotube. Carbon nanotube properties depend on how you roll the sheet. In other words, even though all carbon nanotubes are made of carbon, they can be very different from one another based on how you align the individual atoms.With the right arrangement of atoms, you can create a carbon nanotube that's hundreds of times stronger than steel, but six times lighter Engineers plan to make building material out of carbon nanotubes, particularly for things like cars and airplanes. Lighter vehicles would mean better fuel efficiency, and the added strength translates to increased passenger safety.Carbon nanotubes can also be effective semiconductors with the right arrangement of atoms. Scientists are still working on finding ways to make carbon nanotubes a realistic option for transistors in microprocessors and other electronics.

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Carbon NanotubeDiscovered in 1991 by LijimaIt has Unique material propertiesThey are nearly One-dimensional structuresThere are two types Single-walled and Multi-walled

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Introduction: nanotube structure

Roll a Graphene sheet in a certain direction:Armchair structureZigzag structureChiral structure

Single-walled carbon nanotubes exist in a variety of structures corresponding to the many ways a sheet of Graphene can be wrapped into a seamless tube. Each structure has a Wrapping Angle say (a).

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Rolling a graphene sheet to get SWNT

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Armchair

The armchair structures, with a = 30, have metallic character

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

ZigzagThe zigzag tubes, for which a = 0, can be either semimetallic or semiconducting, depending on the specific diameter.

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Chiral

Nanotubes with chiral angles intermediate between 0 and 30 include both semimetals and semiconductors. (Armchair and zigzag refer to the pattern of carboncarbon bonds along a tubes circumference.)

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Special propertiesDifference in chemical reactivity for end caps and side wallHigh axial mechanical strengthSpecial electrical properties:MetallicSemi conducting

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

11Averzs Technologies

Properties of nanotubes CNTs have High Electrical Conductivity CNTs have Very High Tensile Strength CNT are Highly Flexible- can be bent considerably without damage CNTs are Very Elastic ~18% elongation to failure CNTs have High Thermal Conductivity CNTs have a Low Thermal Expansion Coefficient CNTs are Good Electron Field Emitters CNTs have a High Aspect Ratio (length = ~1000 x diameter

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

MWNT

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Synthesis: overviewCommonly applied techniques:Chemical Vapor Deposition (CVD)Arc-DischargeLaser ablation

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

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Synthesis: CVD

Gas phase depositionLarge scale possibleRelatively cheap

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Arc discharge

Relatively cheapMany side-productsT2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Synthesis: laser ablation

Use of very strong laser Expensive (energy costs) Commonly appliedT2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Purification

Contaminants: Catalyst particles Carbon clusters Smaller fullerenes: C60 / C70

Demerits in purification of Nanotubes:Completely retain nanotube structureSingle-step purification Only possible on very small scale:Isolation of either semi-conducting SWNTs

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Purification techniquesRemoval of catalyst:Acidic treatment (+ sonication)Thermal oxidationMagnetic separation (Fe)Removal of small fullerenes Micro filtration Extraction with CS2Removal of other carbonaceous impuritiesThermal oxidationSelective functionalisation of nanotubesAnnealingT2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE

Applications

Thermal Conductivity of CNTs Field Emission of CNTs Conductive Plastics with CNTs Energy Storage using CNTs Conductive Adhesives and Connectors with CNTs Molecular Electronics based on CNTs Thermal Materials with CNTs Structural Composites with CNTs Fibers and Fabrics with CNTs Catalyst Supports using CNTs Biomedical Applications of CNTs Air and Water Filtration using CNTs Ceramic Applications with CNTs

T2, Reshma Apartments, 3rd Floor, No.324, MKN Road, Alandur , Chennai 16Mobile: 95000 48577, 96000 88172, Mail:[email protected], URL: www.averzs.comAVERZS TECHNOLOGIESA leading Research and Development Division EMERGING EXCELLENCE