O graphene is a two-dimensional crystal formed by bonds between carbon atoms, with hexagons that form something like a wire mesh or a goal mesh. It is, therefore, another synthetic allotrope of carbon, coming from one of its natural allotropes, graphite, the same used in pencils for writing. This material has extraordinary properties, such as those shown below:
é very fine - it is an atom thick;
é highly resistant – it is about 200 times stronger than steel and stronger than diamond, within its proportions;
é flexible;
Graphene is a light, flexible, very resistant and transparent material
has high thermal and electrical conductivity - its electrical conductivity is 100 times faster than copper, which is the most used conductor in the world. Initial studies showed that the velocity of electrons in graphene is 1000 km/s (60 times faster than silicon, which is the element currently used in semiconductors, transistors for chips, solar cells and a multitude of electronic circuits) and can reach a speed of 3000 km/s with a very good quality of this crystal;
é waterproof – being able to block even helium, an extremely light gas;
has high hardness;
é very light and thin, like carbon fiber, but more flexible. With 1.0 gram of graphene, it is possible to cover a surface of 2700 m2;
has less Joule effect – loses less energy in the form of heat by conducting electrons;
é transparent - transmits 97.5% of the light;
é cheap - its raw material is abundant (graphene can come from any carbon material);
can self-repair-if.
The properties of this material began to be further studied and disclosed in 2004 by scientists Andre Geim and Konstantin Novoselov, from University of Manchester, who therefore received the 2010 Nobel Prize in Physics. They obtained graphene when cleaning the surface of a graphite board, gradually wearing it down with adhesive tape.. When they analyzed the graphite residue that remained on the tape under an atomic microscope, they saw that these residues maintained the hexagonal crystal structure of graphite and which also had a peculiar symmetrical arrangement of electrons that increased their conductivity. In graphene, electrons behave as if they had no mass. Tests showed that it worked very well as a transistor.
Andre Geim and Konstantin Novoselov won the 2010 Nobel Prize in Physics for graphene-related discoveries *
As shown in the text carbon allotropy, graphite is formed by plates or layers of hexagons that are attracted to each other in space. Graphene is formed by only one of these plates, having nanometric proportions (1 nanometer is equal to a billionth part of a meter (10-9 m)). You carbon nanotubes they are wrapped graphenes. The other synthetic allotropic form of carbon, the C60 (buckminterfullerene), is like graphene folded into the shape of a soccer ball.
Carbon allotrope structures - graphene, graphite, C-60 and carbon nanotube
Thus, since all the qualities mentioned were found in a single material, the research about the possibilities of using graphene have leveraged, promising to be a revolution technological.
Among the possible applications of graphene that could change the world we know are:
It hasdisplays flexible that can be folded. An example are the screens of tablets and smartphones which, when they fall, they break. Graphene would be used to produce a touch screen (touch screen), flexible, transparent and unbreakable. It would replace the ITO (indium-doped tin oxide) currently used in sensitive screens;
speed up the internet. Graphene has been shown to be able to convert optical to electrical information at a speed around 100 times faster than electrical converters;
can be used in electronics to dissipate heat;
In the production of sensors, as graphene is entirely formed by surface area;
In photonic devices;
Atindustry aerospace, naval, automotive and civil;
In the production of composites;
Atbiomedical area, for example, to make flexible and lightweight prostheses as well as implants;
in telecommunications;
In power generation, such as in solar panels, hydrogen cells and long-lasting batteries;
On more sensitive still cameras;
On high speed cables;
In paintings that absorb energy.
The European Community has launched a program that will allocate one billion dollars to research on graphene in several countries. Research on this material in Brazil is carried out mainly at Universidade Presbiteriana Mackenzie, which invested 30 million reais to create the MackGrafe, a research center on graphene.
It remains to be seen which applications of graphene will actually become a reality in our society.
* Image copyrighted: rook76/Shutterstock.com
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/grafenouma-revolucao-tecnologica.htm