Carbon nano tubes

CARBON NANO TUBESD.AKSHAYAB.TECH IT-A

WHAT ARE CARBON NANO TUBES?

An allotrope of carbon Allotrope- different structural form of the

same element(here carbon) Fullerene family-entirely made of carbon Rolled-graphene structures

ALLOTROPES OF CARBON

carbon

Diamond Graphite Fullerene

DIAMOND AND GRAPHITE Diamond-carbon

atoms tetrahedrally linked covalent bonds in -3D

Hybridisation- sp3

Non-conductor

Graphite-Hexagonally linked carbon atoms

Hybridisation-sp2

Conductor-as it contains unpaired electrons

3

FULLERENES They are molecules composed entirely

of carbon, which take the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are sometimes called buckyballs, while cylindrical fullerenes are called buckytubes or nanotubes.

BUCKY BALLSpherical in shape .A ball with 32 faces. Of the 32 faces, 12 pentagons and 20 hexagons . Looks exactly like a soccer ball(FOOTBALL)

BUCKY TUBES Carbon nano tubes- name is derived from their size,

since the diameter of a nanotube is of the order of a few nanometers (1/50,000 times the width of a human hair) while they can be up to several centimeters in length

TYPES OF CNT

No.of sheets rolled

•Single walled-CNT(SWNT)•Multi walled-CNT(MWNT)

Direction of rolling

•Zig-zag•Arm-chair•Chiral

SWNT & MWNT SWNT-single

sheet of graphene

MWNT- multiple sheets of graphene rolled about a common axis(i.e concentric circles)

ZIG-ZAG,ARMCHAIR &CHIRAL CNT

PROPERTIESELECTRICAL

•The direction of rolling determines the electrical properties•Arm chair-metallic(conducting)•Chiral CNT- semiconducting•Generally CNT-1/3 metallic and 2/3 semiconducting properties in CNT•The band gap is inversely is proportional to its diameter (semiconducting CNT)

MECHANICAL

• The Young's modulus is over 1 Tera Pascal(Larger the young’s modulus, lesser is the stability)•It is stiff as diamond•The estimated tensile strength is 200 Giga Pascal•It is 10 times stronger than steel

OPTICAL

•Efficiently absorbs-uv,visible and IR rays-used in solar panels

•Absorption of electromagnetic waves especially microwaves helps enhancing stealth characteristics of military vehicles &aircrafts

APPLICATIONS OF CNT Textiles-water proof &tear resistant

fabrics Combat jackets/body armour-bullet

proof wears Constructions-CNT bridges replacing

steel suspensions As super-conductors,diodes,transistors As capacitors-to increase charging

ability BUCKY PAPER-250 times stronger than

steel & 10 times lighter than it-used as “Faraday cage” to protect airplanes, electric devices

FIELD OF MEDICINE Artificial muscles-sufficient contractility Scaffold materials for osteoblast

proliferation and bone formationOther uses: Air pollution filter Desalination of water-Reverse Osmosis POLYETHYLENE+CNT- elastic modulus >

30% Hydrogen storage 65% by weight

GEODESIC-DOME-MONTREAL,CANADA

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