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Nanotechnology - Graphene

A presentation on the amazing nanomaterial of graphene and also nanomaterials as a whole.
by

Nathan Morgan

on 9 May 2013

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Transcript of Nanotechnology - Graphene

The scale of all things Aspects of Chemical Bonding within nanoscience materials Here are some images to put the size into scale - quite literally: The one main factor that causes the properties of nanomaterials to be special is their structure. Their tiny structure means they have a greater surface area than other materials and this can alter or improve properties such as strength and electrical characteristics. Myths & Legends Nanotechnology - Graphene How tape will change the world as we know it Information on Graphene Graphene is a material composed of pure carbon, with atoms arranged in a regular hexagonal pattern. Graphene is a one atom thick layer of pure graphite. This means, many layer of graphene make crystalline flake graphite. Graphene is made by heating up the electronic material of silicon carbide. When this silicon carbide is heated up, the remaining residue reconstructs itself into graphene layers. This can be many layers or few layers. The more common way (and the way it was discovered at the University of Manchester) is using tape to peel off individual layers until only one remains. Graphene is the world's thinnest, lightest and strongest material in existance (it is even stronger than diamond , it's 100x stronger than steel and is also the only 2D material). It is also transparent, conducts better than copper and is bendable so can take any form required. Graphene is the perfect thermal conductor with higher thermal conductivity than all carbon structure, i.e. nanotubes and diamond. It's applications are endless, from bendy screens, to a rust resistant layer on metals! Due to it's conductivity, it is thought that it will replace silicon in computer processors and rigid structures for screens. A recent discovery has also shown that it could be used as paint, this means you could power things directly from the wall. Walls could also change colour and generate electricity on the outside of a house (it is thought to be at least as effective as solar panels at generating electricity from sunlight). Nanomaterials The dictionary definition of nanotechnology is: The branch of technology that deals with dimensions and tolerances of less than 100 nanometers, especially the manipulation of individual atoms and molecules. The dictionary definition of nanoscience is: The study of the performance of ultra-small structures, materials, and devices, usually 0.1 to 100 nm; also, the study of manipulating materials on an atomic or molecular scale. Uses of nanomaterials:


New catalysts - They are so small and more efficient
New coatings - As with Graphene, they can improve an existing material's properties
New computers / parts in a computer
Stronger and lighter building materials
Sensors that detect individual substances in tiny amounts Sources: BBC Biteseize - Nanoscience: http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/bonding/structure_propertiesrev7.shtml Manchester University - Microsite on Graphene - http://www.graphene.manchester.ac.uk/index.html BBC News article - Basic Properties of Graphene and its future -http://www.bbc.co.uk/news/science-environment-21014297 Telegraph article - Reasearch into new uses, paint etc. - http://www.telegraph.co.uk/technology/news/10033806/Graphene-paint-could-power-homes-of-the-future.html The bond length between the two carbon atoms is 0.142 nm Carbon Nanotubes are only found in materials that contain carbon, they are cylindrical structures that tend to be very tiny (diameter 1nm)Although carbon nanotubes are strong, they are not brittle. They can be bent, and when released, they will spring back to their original shape. This results in a more strong, but flexible structure. Nanotubes one type has a cylindrical shape with open ends Another type of nanotube has closed ends, formed by some of the carbon atoms combining into pentagons on the end of the nanotube. The electrical properties of carbon nanotubes depend on how the hexagons are orientated along the axis of the tube. Three orientations are possible: armchair, zigzag, and chiral. Armchair carbon nanotubes have electrical properties similar to metals. When you apply a voltage between two ends of an armchair nanotube, a current will flow. An armchair carbon nanotube is a better conductor than copper or any other metal. The zigzag and chiral carbon nanotubes share electrical properties similar to semiconductors. These two configurations of nanotubes will only conduct an electric current when extra energy in the form of light or an electric field is applied to free electrons from the carbon atoms. Semiconducting nanotubes could be useful in building ever smaller transistors used in integrated circuits for all kinds of electronic devices. BONDING The carbon atoms in nanotubes are great at forming covalent bonds with many other types of atoms for several reasons:

Carbon atoms have a natural capacity to form covalent bonds with many other elements because of a property called electronegativity. Electronegativity is a measure of how strongly an atom holds onto electrons orbiting about it. Because carbon has an electronegativity rating in the middle of the range, it can form stable covalent bonds with a large number of elements.

All the carbon atoms in nanotubes are on the surface of the nanotube and therefore accessible to other atoms.

The carbon atoms in nanotubes are bonded to only three other atoms, so they have the capability to bond to a fourth atom. Grey goo Grey goo is a hypothetical end-of-the-world scenario involving molecular nanotechnology in which out-of-control self-replicating robots consume all matter on Earth while building more of themselves, a scenario that has been called ecophagy which means eating the environment. The original idea assumed machines designed to have this capability, while others have assumed that machines might somehow gain this capability by accident. Medical Nanorobots The most popular myth about the millions of nanorobots that will be snooping around in our body, diagnose a variety of cells and tissues to repair the damage with nanoskalpel, dissect and remove cancer cells, increase bone assemblage of atoms,scrape with cholesterol plaques nanoshovel,and in the brain selectively break synapses, responsible for the unpleasant memories. Public Comments & Pros 'n' Cons of Nanoscience Prince Charles Prince Charles opinion on Nanoscience & Nanotechnology is that it's a huge threat to the world, as he believes that "grey goo" could one day be what's left of the planet However his comments are unrealistic due to the fact that the possibility of Nanoscience being developed to an extent of robots being able to change the Earth into goo is about the same possibility of time travel being created. Pro's 'n' Cons Pro's Cons Nanotechnology can actually revolutionize a lot of electronic products, procedures, and applications. The areas that benefit from the continued development of nanotechnology when it comes to electronic products include nano transistors, nano diodes, OLED, plasma displays, quantum computers, and many more.
Nanotechnology can also benefit the energy sector. The development of more effective energy-producing, energy-absorbing, and energy storage products in smaller and more efficient devices is possible with this technology. Such items like batteries, fuel cells, and solar cells can be built smaller but can be made to be more effective with this technology.
Another industry that can benefit from nanotechnology is the manufacturing sector that will need materials like nanotubes, aerogels, nano particles, and other similar items to produce their products with. These materials are often stronger, more durable, and lighter than those that are not produced with the help of nanotechnology.
In the medical world, nanotechnology is also seen as a boon since these can help with creating what is called smart drugs. These help cure people faster and without the side effects that other traditional drugs have. You will also find that the research of nanotechnology in medicine is now focusing on areas like tissue regeneration, bone repair, immunity and even cures for such ailments like cancer, diabetes, and other life threatening diseases. Possible loss of jobs in the traditional farming and manufacturing industry
The development of nanotechnology can also bring about the crash of certain markets due to the lowering of the value of oil and diamonds due to the possibility of developing alternative sources of energy that are more efficient and won’t require the use of fossil fuels. This can also mean that since people can now develop products at the molecular level, diamonds will also lose its value since it can now be mass produced.
Atomic weapons can now be more accessible and made to be more powerful and more destructive. These can also become more accessible with nanotechnology.
Since these particles are very small, problems can actually arise from the inhalation of these minute particles, much like the problems a person gets from inhaling minute asbestos particles.
Presently, nanotechnology is very expensive and developing it can cost you a lot of money. It is also pretty difficult to manufacture, which is probably why products made with nanotechnology are more expensive. Our brains
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