Naveed Akhtar

LS1201201

Introduction

Types

Properties

Production

Applications

Conclusion

References

Questions

Allotropes of carbon with a cylindrical structure

Composed entirely of sp2 bonds

Walls are formed by one-atom-thick sheets of carbon called graphene

Can be capped on the ends with buckyballs or open ended

Diameter range 0.4–40 nm but the length reach upto18.5 cm

Nanomaterials

Organic

Fullerenes

C60

C90

Carbon Nanotubes

Multi-walled

Single-walled

Inorganic

Metal Oxides

ZnO2

CeO2

Metals

Au

Ag

Quantaum Dots

CdSe

Armchair Zig-Zag

Multiple rolled layers of

graphene sheets

Russian Doll model, sheets

of graphite are arranged in

concentric cylinders

Parchment model, a single

sheet of graphite is rolled

in around itself

Interlayer distance ~ 3.4Å

A) Young Modulus (stiffness) Carbon nanotubes 1250 GPa

Carbon fibers 425 GPa (max.)

High strength steel 200 GPa

B) Tensile strength (breaking strength) Carbon nanotubes 11- 63 GPa

Carbon fibers 3.5 - 6 GPa

High strength steel ~ 2 Gpa

C) Density Carbon nanotube (SW) 1.33 – 1.40 gram / cm3

Aluminium 2.7 gram / cm3

Carbon nanotubes are the strongest ever known material

Armchair structure nanotubes show

the metallic electrical properties

Chiral structure nanotubes are

semiconductors

Metallic nanotubes can carry an

electrical current density of 4×109

A/cm2 which is more than 1,000

times greater than metals such as

copper

Electrons propagate only along the

tube's axis, so CNT referred to as

one-dimensional conductors

All nanotubes are expected to be very good thermal

conductors along the tube, but good insulators

laterally to the tube axis.

It is predicted that carbon nanotubes will be able to

transmit up to 6000 watts per meter per Kelvin at

room temperature; compare this to copper, a metal

well-known for its good thermal conductivity, which

transmits 385 watts per meter per Kelvin.

The temperature stability of carbon nanotubes is

estimated to be up to 2800oC in vacuum and about

750oC in air

Because of the very small structure of CNTs, the tensile strength of

the tube is dependent on its weakest segment in a similar manner

to a chain, where the strength of the weakest link becomes the

maximum strength of the chain.

High level of defects can lower the tensile strength up to 85%

Low thermal conductivity

Low Electrical properties

Defects can occur in the form

of atomic vacancies

Crystallographic defect

Common Methods

Uses two carbon electrodes that are separated by 1 mm and located in a partial vacuum

25 V is applied across the electrodes, causing carbon atoms to be ejected from positive electrode and carried to negative electrode where they form nanotubes• If no catalyst – multi-walled

nanotubes form

• If cobalt used as catalyst, single-walled nanotubes with diameters 1 to 5 nm and lengths ~ 1 m

Starting material is graphite with traces of Co and Ni that act as nucleation sites in formation of nanotubes

Graphite work piece is placed in quartz tube filled with argon and heated to 1200°C

A pulsed laser beam is focused on surface, causing carbon atoms to evaporate from the bulk graphite

Argon moves carbon atoms to cool copper surface, where they condense, forming nanotubes with diameters 10 to 20 nm and lengths ~ 100 m

Starting material is hydrocarbon gas such as methane (CH4) Gas is heated to 1100°C, causing it to decompose and release

carbon atoms Atoms condense on cool substrate to form nanotubes Substrate surface may contain metallic traces that act as

nucleation sites for nanotubes CVD process can be operated continuously, making it attractive

for mass production

Structural Applications

Electrical Applications

Energy Storage Applications

Biomedical Applications

Weaving them into clothes to create stab-

proof and bulletproof clothing

CNTs are being coated on the fiber

surface for preparing multifunctional

fabric including antibacterial, flame

retardant

CNT composites that incorporate tougher

materials (i.e. Kevlar)

Field Emission Display ( FED)Uses electron beam to produce color images

Nano electrical cables and wires

FED LCD CRT EL

Low Cost

Wide

Viewing

Angle

Rugged

Sharpness

Low Power

High

Resolution

Thin

Lightweight

Paper batteries

Solar cells

Ultracapacitors

Hydrogen storage

Physical or chemisorption

Li

ion

ba

tte

ry

Designing novel carbon nanostructures for hydrogen storage

G. Dimitrakakis, G. Froudakis, and E. Tylianakis

Pillared graphene provides a stable architecture for enhanced fuel storage

8 March 2009, SPIE Newsroom. DOI: 10.1117/2.1200902.1451

Pillared graphene consists of CNTs and graphene sheets combined to form a 3D

network nanostructure

Ferromagnetic nano-container for diagnostic and therapy of cancer

1.Transfer of (functionalized) ferromagnetic nanotubes in cells

2.Manipulation by external magnetic fields (e.g. alignment, heating)

3.Detection of magnetic particles by magnetic probes (SQUID, NMR,

etc.)

Because of their unique properties CNT are making their way in a wide range of fields from engineering to medicine.

However, there are concerns over the similar shape of nanotubes and asbestos fibers, which are known to cause damage to the lungs in conditions such as mesothelioma.

Scientists are therefore trying to work out if there are any adverse effects that nanotubes might have on human health.

In a new study on mice, researchers found that inhaling nanotubes affected the function of T-cells, a type of white blood cell that organizes the immune system to fight infections.

Having unique properties

Many ways to synthesize

Method of synthesis depends on finances

involved and amount of product desired

There are many exciting applications of

carbon nanotubes

Special properties & potential

applications make them material of future

http://www.news-medical.net/news/22799.aspx

Chae, H.G.; Kumar, S. (2006). "Rigid Rod Polymeric Fibers". Journal of

Applied Polymer Science 100:791-802: 791. doi:10.1002/app.22680.

Hong, Seunghun; Sung Myung (2007). "Nanotube Electronics: A flexible

approach to mobility". Nature Nanotechnology 2: 207–208.

doi:10.1038/nnano.2007.89

Meo, S.B.; Andrews R. (2001). "Carbon Nanotubes: Synthesis, Properties,

and Applications". Crit. Rev. Solid State Mater. Sci. 26(3):145-249: 145.

doi:10.1080/20014091104189.

Kolosnjaj J, Szwarc H, Moussa F (2007). "Toxicity studies of carbon

nanotubes". Adv Exp Med Biol. 620: 181–204. PMID 18217344

Ebbesen, T. W.; Ajayan, P. M. (1992). "Large-scale synthesis of carbon

nanotubes". Nature 358: 220–222. doi:10.1038/358220a0

http://www.nanowerk.com/spotlight/spotid=4154.php

http://www.azonano.com/details.asp?ArticleID=980#_Energy_Storage

http://www.azonano.com/details.asp?ArticleID=1561

http://www.nanotechnology.de/ntforum/download/16_Buechner_Leibniz_I

FW.pdf