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Graphene the wonder material

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Rafael Ng

on 12 April 2013

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Transcript of Graphene the wonder material

Graphene What is it? Wonder Material
of the future Now take one of the layers out and it should look like this honeycomb structure here. Congratulations, you now know what Graphene looks like, i.e. a one atomic layer thick sheet of pure carbon. When was it first made? It was first made in 2004 by Andre Geim and Kostya Novoselov at the University of Manchester. They later won the 2010 Nobel Prize for Chemistry. Novoselov Geim They did this using a chunk of graphite and sticky tape. These bonds are easy to break These are not Imagine a molecule of graphite. You see hexagonal sheets of carbon stacked on top of each other. How else is it synthesized? A sheet of Graphene under a Scanning Electron Microscope Graphene can also be synthesized in
many other ways.
For example, you could heat silicon carbide to above 1,100 degrees C under low pressure to reduce the top layer to Graphene. Silicon Carbide (SiC) Another way of making Graphene is to
cut open carbon nanotubes, which is
basically rolled-up Graphene,
using chemicals such as sulfuric
acid or potassium permanganate. Carbon Nanotube A third way to do this is to disperse graphite in a liquid and then blast it with sound. Then you put it in a centrifuge to separate the Graphene from the liquid. This is a centrifuge, not a rice cooker What properties does it have? Potassium
Permanganate Sulfuric acid High Conductivity! Electrons literally travel through Graphene as if they had no mass at 3,000,000 metres per second. Electron Zoom! This is partly due to low electrical resistance, which results in there being little electron scattering, which slows down electrons as they go through conductors. Almost-Weightlessness!
It's only one atomic layer thick, so one square-meter of it would weigh 0.77 milligrams. Almost-Transparency!
A layer of Graphene only absorbs 2.3% of the light that falls on it and 2 layers of Graphene will absorb twice as much. Superstrength!
300 times stronger than steel and much harder than diamond! One square-meter can support a 4kg cat. Flexibility!
Can be scrolled up or folded like plastic film! Can also be stretched 20% of its length whilst retaining its structure. In July 2012, Graphene was accidentally found to
repair any holes in it when there are stray
carbon atoms lying around. Graphene with a hole in it. Generates light when hit by any
type of light at any temperature! This is due to the 'Hot Carrier' effect. Previously, this could only be done when the materials used were cooled to near absolute zero or when blasted with a powerful laser. Light Electricity Applications? Graphene Solar Panels! As mentioned before, Graphene generates
electricity when hit by light at any temperature. Example of Graphene solar panel Graphene Touchscreens! Graphene is a rare combination of transparency and conductivity, making it ideal for touchscreens. Modern touchscreens contain indium tin oxide and indium is very rare, whereas carbon is very common. Touchscreen in serious need of Graphene Graphene Desalination! Graphene with tiny pores in it of just the
right size will only let water through while
blocking everything else! Due to its thinness, it also takes very little pressure and therefore energy to force the water through it. Graphene desalination. Notice the hole somewhere on the Graphene sheet. Graphene Computer Chips! Remember when I said that electrons in Graphene move very quickly? This could potentially make computers run much much faster. Self-Reparation! Looks like this but with more Graphene Graphene Batteries! They could charge in a few
seconds and due to their high
surface area-to-volume ratio, they
could store a lot of energy. Meh, needs more Graphene Graphene Earphones! Graphene can be used as the diaphragm in an
earphone, because they are strong and best of all, they require no damping at all. Graphene can be added to tires to make them stronger and more durable as well! Some have even proposed using it to replace the carbon fibres used to build bikes and boats because of its strength. Carbon Fibre Graphene Believe it or not, Graphene even has
medical uses, such as artificial muscles
or prosthetic nerves because of its flexibility and conductivity. Like this but with more Graphene.
And I swear the thing on the
right isn't a brain-sucking alien. Advantages Lightness coupled with Strength
It's not something that many materials have. High Conductivity
It's the closest thing to a room temperature superconductor
we have so far. Versatility! If you were paying attention for the past 5 minutes, this would not
need an explanation Disadvantages Hard to make in large amounts. I dare someone to actually make one square meter of Graphene with a chunk of graphite and some sticky tape It costed $100,000,000/sq.cm in 2008, but now it costs $100/sq.cm. Still pretty expensive though It's not the most expensive thing ever made though. In comparison, it costs $62.5 trillion just to make a gram of anti-hydrogen (a positron and an
anti-proton stuck together). Anyway, we're at the end of the presentation. Some of you may have spotted this if you looked hard enough. This looks kinda like Graphene.
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