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Nanomaterials

YASEMNYILDIZ


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NanotechnologyNanotechnology (sometimes shortenedto "nanotech") is the study of

manipulating matter on an atomic andmolecular scale. Generally,nanotechnology deals with developingmaterials, devices, or other structurespossessing at least one dimension sizedfrom 1 to 100 nanometres


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Impact of

nanotechnologyThe impact of nanotechnology

extends from its medical, ethical, mental,legal and environmental applications, to

fields such as engineering, biology,chemistry, computing, materials science,military applications, andcommunications.

Major benefits of nanotechnology includeimproved manufacturing methods, waterpurification systems, energy systems,physical enhancement, nanomedicine,

better food production methods andnutrition and large scale infrastructure


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What is ananomaterial?

A field that takes a materials science-based approach to nanotechnology

material having at least one dimension 100nanometres or less, up to10,000 could fit

across a human hair. Nanomaterials can benanoscale in one dimension (eg. surfacefilms),two dimensions (eg. strands orfibres), or three dimensions (eg. particles).

They can exist in single, fused, aggregated


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Nanomaterial Composition

Comprised of many different elementssuch as carbons and metals

Combinations of elements can make upnanomaterial grains such as titaniumcarbide and zinc sulfide

Allows construction of new materials suchas C60 (Bucky Balls or fullerenes) andnanotubes


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How they are made

Clay/polymer nanocomposites can bemade by subjecting clay to ion exchange

and then mixing it with polymer melts

Fullerenes can be made by vaporizingcarbon within a gas medium

Current carbon fullerenes are in thegaseous phase although samples of solidstate fullerenes have been found in nature


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Production ofNanomaterials

There are five widely known methods toproduce nanomaterials, and they are as

follows:

Sol-gel synthesis,

Inert gas condensation,

Mechanical alloying or high-energy ball milling,

Plasma synthesis, and

Electrodeposition.


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How can it be used?Engineered nanomaterials are materialsdesigned at the molecular (nanometre) level totake advantage of their small size and differentproperties which are generally not seen in theirconventional, bulk counterparts

Two main reasons why materials at the nanoscale can have different properties are increasedrelative surface area and new quantum effects

Nanomaterials have a much greater surface areato volume ratio than their conventional forms,which can lead to greater chemical reactivity andaffect their strength


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How can it be used?Nanomaterials (nanocrystalline materials) arematerials possessing grain sizes on the order ofa billionth of a meter

manifest extremely fascinating and usefulproperties and exploited for a variety ofstructural and non-structural applications

Since nanomaterials possess unique, beneficial

chemical, physical, and mechanical properties,they can be used for a wide variety ofapplications. These applications include, but arenot limited to, the following:

Next-Generation Computer Chips


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nanomaterials" generally fallinto two categories:

fullerenes, and inorganicnanoparticles


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FULLERENE

A fullerene is any molecule composedentirely of carbon, in the form of a hollow

sphere, ellipsoid or tube. Sphericalfullerenes are also called buckyballs,and they resemble the balls used inassociation football. Cylindrical ones are

called carbon nanotubes or buckytubes.Fullerenes are similar in structure tographite, which is composed of stackedgraphene sheets of linked hexagonalrings; but they may also contain

pentagonal (or sometimes heptagonal)


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Types of Fullerene

Since the discovery of fullerenes in 1985,structural variations on fullerenes have

evolved well beyond the individual clustersthemselves;

Buckyball clusters: smallest member isC20 (unsaturated version of

dodecahedrane) and the most common isC6

Nanotubes: hollow tubes of very smalldimensions, having single or multiple

walls; potential applications in electronics


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Buckyballs

Buckminsterfullerene

Buckminsterfullerene is thesmallest fullerene moleculecontaining pentagonal andhexagonal rings in which no twopentagons share an edge (whichcan be destabilizing, as in

pentalene). It is also the most
http://en.wikipedia.org/wiki/File:Fussball.jpg


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C60 with isosurface of ground stateelectron density as calculated withDFT

Many association footballs have thesame shape as buckminsterfullerene,C60
http://en.wikipedia.org/wiki/File:Fussball.jpg


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Boron

buckyball

A type of buckyball which uses boron atoms, insteadof the usual carbon, was predicted and described in

2007. The B80 structure, with each atom forming 5or 6 bonds, is predicted to be more stable than theC60 buckyball. One reason for this given by theresearchers is that the B-80 is actually more like the

original geodesic dome structure popularized byBuckminster Fuller, which uses triangles rather thanhexagons.

The number of six-member rings in this molecule is

20 and number of five-member rings is 12. There isan additional atom in the center of each six-member


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Other buckyballs

20-fullerene(dodecahedral graph) 24-fullerene 26-fullerene

60-fullerene(truncated

icosahedral graph)

70-fullerene


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Carbon nanotubes

Carbon Nanotube(CNT)

Originally, discovered as by products offullerenes and now are considered to bethe building blocks of future nanoscaleelectronic and mechanical devices.


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Discovery of CNT

(1) Multi-Walled CarbonNanotube(MWNT)

- Sumio Ijyma(Nature,1991)

(2) Single-Walled carbon

Nanotube(SWNT)

- Ijyma,Bethune,et al. (1993)

(3) Single Crystals of SWNT

- R.R.Schlittler,et al. (Science,


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Structure of Nanotube

SWNT atom structures

Basically,sheets of graphite rolled up

into a tube as shown figure.

The hexagonal two dimensional lattice ofgraphite is mapped on a cylinder of radiusR with various helicities characterized bythe rolling vectors.


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Uses of carbon nanotube

These cylindrical carbon molecules havenovel properties that make them

potentially useful in many applications innanotechnology, electronics, optics andother fields of materials science, as well aspotential uses in architectural fields. Theyexhibit extraordinary strength and uniqueelectrical properties, and are efficientthermal conductors.


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Limitation of carbonnanotube

Their final usage, however, may be limitedby their potential toxicity and controlling

their property changes in response tochemical treatment.


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Nanoparticles

Nano: 10-9

Definition: An ultrafine object between 1and 100 nanometers, that may vary inproperties (size-related/chemical related)as their bulk component (E.g. nanoparticleof gold may differ from particle of bulk

gold)

Uses: Medicine, industry, maunufacturing,experiments

Characteristic: High surface area to volumeratio


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Silver Nanoparticles

Size: 10nm-100nm

Chemical formula: Ag

Details: Silver nanoparticles are ultra fineparticles of silver. They are ten to ahundred nanometers large, and differ fromthe bulk silver as they have differentcolours such as yellow, as opposed to thesilver. This is due to plasmon absorbance:

Incident light rays create oscillation in freeelectrons on the surface of nanoparticles,

causing them to absorb electromagnetic


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Uses of Silver

NanoparticlesMedicine and Health

Silver has anti-bacterial properties

Can bind to bacteria molecule

Chemically change bacteria structure andrupture it, eventually killing the cell

Potential cure for HIV

Ability to bind to spikes of HIV virus andprevent it from latching on to cell. Thisensures that the HIV virus does not bind tohost cells and infection can be suppressed

Surgical insturments/masks


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Uses of SilverNanoparticlesHousehold/Industry

Silver Nano

Samsung Produced SilverNano, a patentedproduct that claims to have silvernanoparticles on surfaces of householdparticles for anti-bacterial properties.

Air purifiers

Silver nano particles produced by air purifiersbind to a binding agent in paint known asalkyd resin, which produces toxic freeradicals, which get transformed by silvernano-particles to non-toxic metal


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Gold NanoparticlesSize: 100nm+

Chemical formula: Au

Details: Gold nanoparticles, known as nanogold or colloid gold, is a suspension of sub-micrometre-sized particles (10nm or more)in a fluiod, usually water. If the particle is

less than 100nm, a intense red colour isusually observed, but if larger, a dirtyyellowish colour is observed in thesupension.

This may be due to plasmon absorbance

It is also a semi conductor in which it has


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Uses of Nano GoldMedicine and Health

Arthiritis in rats and dogs

Implantation of nano gold in knee of rat and dog acts

as painkiller

Drug Delivery

Gold can be used as outer covering of drugs, whichmetl to release drug payloads when exposed to

infrared light. Timing of drug release and uptake canthus be better controlled

Alzheimers Disease

Research done that combination of colloisdal gold can

microwave radiation can distroy plaque and fibrils thatbuild u to cause Alzheimers disease


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Uses of Nano GoldMedicine and HealthCancer

Nano gold reflects light very well. Many cancers have

receptors on their outer layers, in which goldnanoparticles can be bound to antibodies which attachto the cancer cell receptors, and can be viewed undersimple white light microscope to detect cancer cells byseeing the reflection of light.

Also, ability for gold nano rods to be inserted intocancer cell to weaken the cancer and eventually kill itposes potential to be cancer cure.

Toxin detection

Nanoparticles can be coated with sugars to detectcertain toxins, in which as the nanoparticle binds to thetoxin the whole solution changes colour to indicate the

presence of the toxin. The device can be sued forportable toxin detection


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Uses of Nano GoldHome/Industry

Stain Glass

Water purification

Used in electronics

Has material compatibility

Durable

Reliable material

Used for touch sensitive screens and alsopotential data storage device use

Makin semiconductor chi work with less


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With regard to gold and silvernanoparticles:

Extremely small

Have medical properties, and can bebeneficial to mankind

Has physical and chemical changes formthe bulk molecule when shrunk to a smallsize

Ability of portable usage since the particlesare very small


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NanotoxicologyNanotoxicology is the study ofthe toxicity of nanomaterials. Because ofquantum size effects and large surface area,nanomaterials have unique properties

compared with their larger counterparts

Nanotoxicology is a branch of bionanosciencewhich deals with the study and application of

toxicity of nanomaterials

Nanotoxicological studies are intended todetermine whether and to what extent theseproperties may pose a threat to theenvironment and to human beings. For


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NanotoxicologySub-specialty of particle toxicology. Itaddresses the toxicologyof nanoparticles (particles


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NanotoxicologyThese differences seem to be a result of their

size. Nanoparticles have much larger surfacearea to unit mass ratios which in some cases

may lead to greater pro-inflammatory effects(in, for example, lung tissue). In additionnanoparticles seem to be able to translocatefrom their site of deposition to distant sites suchas the blood and the brain.

resulted in a sea-change in how particletoxicology is viewed- instead of being confinedto the lungs, nanoparticle toxicologists studythe brain, blood, liver, skin and gut.N t i l h l ti i d ti l

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