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What is Graphene?
Graphene is a 2-D sheet of carbon atoms. These individual atoms form hexagonal lattices and a fascinating substance. If these 2-D sheets are left to interact with each other, they will pile up and form a 3-D substance we call graphite. It is important to note that although many properties are similar between graphite and graphene, they have some unique qualities too. For example, graphite is a brittle material, while graphene is the strongest material known to men. When graphene sheets pile up to form graphite, the forces holding the sheets together are weak. Unlike each individual sheet, the layers of sheets do not have covalent bonds connecting them together. This allows us to leave a trace on a piece of paper with our pencils. The pencil lead is made of graphite and clay. When rubbed against another surface it will leave a colored trace composed of graphite --- sometimes graphene --- and clay.
Where do we find Graphene?
As was mentioned, graphite is composed of graphene. Currently, graphite is extracted from the ground and metamorphic rocks. China has the largest natural supply of graphite. There are several methods that allow scientists to separate graphene sheets from graphite. One of these methods is called the "Scotch Tape Method". In a simplified explanation, scientists are able to peel off the layers of graphene one by one by ripping them off with a piece of sticky paper. Another method involves the oxidization of graphite flakes (a type of graphite mineral) through the use of sulfuric or nitric acid. The oxidization process allows oxygen molecules to slide between the sheets of graphene and force them apart. This produces graphene oxide sheets, ready to be processed further.
What are the properties of Graphene?
According to ATRIA Innovation, the most outstanding properties of graphene are, and I quote: (Click on the arrows to see further comments and definitions)
High thermal conductivity
The thermal conductivity of a material is a measure of its ability to conduct heat.
High electrical conductivity
High elasticity and flexibility
High hardness
High resistance.
Ionizing radiation is not affected
Able to generate electricity by exposure to sunlight
Transparent material
High density.
Antibacterial effect.
Low Joule effect,
Low electricity consumption compared to other compounds
What are its applications?
Graphene is found in the following components and more:
microchips
transistors
conductive inks
batteries
solar panels
security labels - graphene was introduced to the labels of items in shops and composes a circuit that sounds if the label leaves the shop.
padel blades
medical sensors
Visit ATRIA innovation if you want to read about the purpose of graphene in each of these objects.
What are some of the limitations of graphene?
Graphene has great properties, but it also has limitations. For example, although graphene is a great conductor, scientists do not know how to "turn off" this property. This means scientists cannot stop graphene from conducting heat and electricity. Graphene has also been discovered to have some dangerous qualities. On a molecular level, graphene can pierce cell membranes with its pointy edges. Graphene can then enter the cell and disrupt the cell's functions. Lastly, graphene is currently too expensive to produce and transport.
What is the history of graphene?
Check out the last link in the sources for a detailed summary of graphene's discovery.
Sources
This article talks about the advantages and disadvantages of graphene. It also has a small introduction that explains what graphene is.
This article explores the possibility of using graphene as a power source in the form of paint. Since graphene is able to create electricity from sunlight, it could be coated on the exterior walls of buildings.
This article talks about graphite and its properties.
This is an MIT article about graphene. It talks about the extraction of graphene sheets from graphite.
This article talks about pencil lead. From its composition to different types of leads, you should find everything you could ever want to know about pencil lead.
This video shows what graphite and graphene look like on a molecular level. The speaker also talks about some properties of the two materials.
This article goes over some of the applications and properties of graphene. It has detailed explanations for the purpose of graphene in each of the objects I mentioned in the article.
This video summarizes my whole article into a 2-minute video.
This article goes over the history of the material. The website also has many other web articles about graphene, its qualities, limitations, uses, etc.
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