What’s so big about

nano? ZoeSchnepp

New materials

• Know that a range of new materials are being developed that involve the use of nanoparticles.(D-C)

• Know the size of nanoparticles and be able to find out about carbon nanoparticles (D-C)

• Explain how nanoparticles are different from ordinary sized particles of the same material. (B-A*)

• http://www.youtube.com/watch?v=5jqQxuVncmc

Nanoscience• Use the information supplied to make

simple notes about the SIZE of nanoparticles, the properties of particular nanoparticles, how they are different from the properties of the ordinary bulk materials.

• Describe and explain particular applications of nanomaterials.

•

• Nanoscience• Nanoparticles vary between 10 and 1000 atoms in size.• In this size range properties of materials change. e.g. Nanosilver

becomes antiviral, antifungal and antibacterial so sprays can be used to clean operating theatres in hospitals and coat the inner surfaces of fridges. Titanium dioxide can be used in sunscreens because it blocks uv light but is transparent so does not cause white smears on the skin.

• Other opaque substances become transparent (copper), unreactive materials become catalysts (platinum and gold),insulators become conductors (silicon) and materials change colour (e.g. gold nanaparticles are deep red in solution.)

• Health.• Early detection of cancer and targeted drug delivery improve survival

rates.• Possible risks:• Easy absorption through skin may lead to long term, harmful effects.• http://www.youtube.com/watch?v=5jqQxuVncmc

NANOSCIENCE

Refers to the science of structures that are 1–100nm in size

Nanoparticles Show different properties to the same materials in bulk and have a high surface area to volume ratio

This can lead to the development of…

new computersnew catalystshighly selective sensorsnew coatingsstronger and lighter construction materialsnew cosmetics such as sun-tan creams and deodorants

Scientifically, NANO means one thousand millionth (10-9)

Buckyball(~1nm)

DNA(~2nm diameter)

Red blood cells(~2-5μm)

Hair (~60-120μm)

Virus(10-300nm)

Gold atom(135pm)

www.nature.com/physics/highlights/6999-1.html

10mm

1mm (1,000,000nm)

0.1mm

0.01mm

0.001mm, 1μm (1000nm)

0.1μm (100nm)

0.01μm (10nm)

1nm

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0.1nm

10-2m

10-3m

10-4m

10-5m

10-6m

10-7m

10-8m

10-9m

10-10m

X-ra

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WHAT IS NANO?

100nm

Gold nanoparticles

Image courtesy of Martin Hollamby

Gold nanoparticles

5nm

Image courtesy of Dr Sean Davis

Grey goo?

Lots of people suspicious of nanotechnology

Worries about nano-robots that could self-replicate

• Not that realistic

• Brownian motion

• Surface forces

BUT… body cells are effectively machines, with

working parts on the nano-scale so nature has done

it

The real safety issue

• Nanoparticles can be much more reactive than bulk material

• Physical shape of material can seriously affect its toxicity

e.g. Asbestos

Serpentine – flat sheets of atoms, harmless

Chrysotile – nano-scale tubes- Cause lung cancer

Should treat these new nano-materials with caution

Properties of Nanoparticles

The properties of substances change entirely when in nano-sized

form.

silver

e.g.

Silver (macro)Silver is a ductile and malleable metal (slightly harder than gold). It’s white with a metallic sheen capable of high shine. It has the highest electrical conductivity of any metal, even copper, and so is used to coat high quality electrodes/ electronic connections.Pure silver also has the highest heat conductivity of all metals (diamond is the only non-metal that’s higher).Because it reflects well, it’s used as a background for mirrors. Silver salts react to light, and silver nitrate is used in photographic film.G

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Properties of Nanoparticles

The properties of substances change entirely when in nano-sized

form.

Silver (nano)

Silver in this form shows different properties:

1) It’s antibacterial2) It’s antiviral3) It’s antifungal

In each of the above examples, the silver nanoparticles prevent the organism’s respiratory enzymes from working, and so kills them in minutes.

Special socks are now available that include silver nanoparticles in order to heal conditions such as athlete’s foot. Research has shown that silver can also be used to treat many diseases, from flu to HIV. G

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Using Silver Nanoparticles

Coating the inside of the fridge with silver nanoparticles ensures that any microbe is killed and keeps the fridge clean hygienic and safe.

Nanoparticles in the washing machine ensure that the clothes are cleaned and disinfected.

The silver nanoparticles in this sock kills odour causing bacteria and keep the socks fresh!

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Advantages and disadvantages of using

nanoparticles

Nanoparticles

AdvantagesDisadvantages

Preparation of certain catalysts

Unusual propertie

s,

leading to new uses

Some have antibacterial,

antiviral and antifungal properties

Could penetrate skin and cause undesired

side-effects

Easily releasedinto the environment

There is a lot that we don’t know about nanoparticles at the moment. Much more research is needed before their use becomes widespread

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