what’s so big about nano? zoe schnepp. new materials know that a range of new materials are being...
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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
Ultr
avio
let
Infr
ared
Mic
row
ave
0.1nm
10-2m
10-3m
10-4m
10-5m
10-6m
10-7m
10-8m
10-9m
10-10m
X-ra
y
WHAT IS NANO?
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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