The Chemistry of Graphene

Introduction

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Graphene is a single layer, 2 dimensional form of carbon that is stronger than steel, a better conductor than any other material, and a revolutionary substance.  I chose to research this because it is a fairly new discovery in the fields of technology, physics, and chemistry, all areas that I am hoping to pursue further in college.  Because of its recent discovery, graphene is still in the beginning stages of mass production, therefore it is not present in everyday life.  However, graphene research is on the rise, and graphene related products can actually be purchased.  With the discovery of more effective methods of production, graphene will be seen more often in our everyday lives.

Composition of ...

The main and only component of graphene is carbon.  Graphene is just a single atom thick version of a more common, naturally occurring form of carbon, graphite.  Graphene is made of the carbon-12 isotope of the base element carbon, meaning it has 6 protons, 6 neutrons, and 6 electrons.  The outermost energy level has 4 valence electrons, which makes it much easier to create bonds with other atoms.  the carbon atoms create a hexagonal pattern, from which many of graphene’s properties derive.



Main Chemicals, Compounds, Components

As stated earlier, graphene is made entirely of carbon-12 atoms.  Each carbon atom bonds with three other carbons.  The only way that this can occur is in a hexagonal pattern.  This hexagonal pattern can repeat over and over again, for any length.  The structure contributes to most of the properties of graphene.  The important properties of conductivity of heat and electricity stem from this structure.  Electrons can move freely around the highly connected structure, and heat transfers very easily through the shape.  Another important aspect of the structure is that at the most basic level, graphene is one atom thick, but it can be stacked to create a cohesive, multilayer structure.  On the most basic scale graphene is considered two-dimensional, which is another great property.

Chemistry's Role

As with all things in this world, Graphene has a great relevance to chemistry.  The first question to ask is whether graphene occurs naturally in this world.  The answer to that is both yes and no.  Graphite, a naturally occurring form of carbon, is essentially many layers of graphene.  However, graphene does not exist naturally in a single layer form.  Because it is separated in a lab, that means that it is difficult to create in large amounts, spiking the value of the product.  The way to create graphene is surprisingly simple, but very time consuming.  While scientists are trying to discover a more effective method, the current method that is used the most is the Scotch Tape method. On a very basic level, scientists put tape on graphite and peal it back, a process which takes only a few layers of graphite.  This process is repeated until it becomes one layer thick.

Graphene has many stupendous qualities, all of which are because of its chemistry.  One important aspect of graphene is that it is transparent.  It absorbs only 2% of light that is shined on it. This is because there is space between that atoms, and because of its sheer thinness. A stack of graphene layers would catch more light, but because graphene is so thin it lets most of it through.  Another important characteristic that can be explained using chemistry is its strength, being 200 times stronger than steel.  Each carbon bonds with three other carbon atoms, and the bonds are very strong because they are covalent. This is surprising because it is also very flexible. Graphene is also one of the best conductors of electricity.  This is because electrons, the base of electricity, can flow across the tight covalently bonded carbon atoms.  Covalent bonds allow for electrons to move more quickly, and the hexagonal shape helps benefit that.  Graphene also is the best conductor of heat known to man.  It is superior to all other materials.  It is also incredibly light, weighing only .78 milligrams per square meter, meaning that a sheet of graphene the size of a football field would weigh around 3.8 grams.  One important fact about graphene is that when it becomes too large, it loses some of its properties.


Background Research

Graphene was first discovered in 2004 by Andre Geim and his assistant Kostya Novoselov, both professors at the University of Manchester.  Although they were the ones to discover it, the concept of graphene was first explored by P. R. Wallace in 1947, who explored the properties of graphene’s three dimensional counterpart, graphite.  Before monolayer graphene was separated, a different type of graphene was “grown” on other metals, called epitaxial graphene.  Now, the collecting of graphene is done using micromechanical cleavage, or using an adhesive substance to take a few layers of bulk graphite at a time. When this process is repeated, a single layer of graphene can be extracted.  Because graphene is a single layer, it has the properties of immense strength, great conductivity of heat and electricity, and near transparency.

Resources

http://www.graphenea.com/pages/graphene#.VmjjVBqDGkq

What is graphene?

Pure carbon

Hexagonal shape

Single layer, one atom thick

Molecule bond length of .124 nanometers

It is the smallest form of graphite, stacks of it create graphite oxide when also combined with oxygen

Thinnest compound known to man

100-300 times stronger than steel

Properties of graphene

Fundamental Characteristics

http://www.newyorker.com/magazine/2014/12/22/material-question

How it was discovered by Andre Geim and Kostya Novoselov

Propertes


http://www.graphene.manchester.ac.uk/explore/the-story-of-graphene/

Discovered at University of Manchester

Properties and uses

In 2004

1984 was first theoretically proposed

Kostya Novoselov worked with Andre

Can possibly be used for water purification

Immense properties that can be useful

https://en.wikipedia.org/wiki/Graphene#History

Graphite intercalation Compounds

What it came from

Crystalline allotrope

http://www.nature.com/news/graphene-the-quest-for-supercarbon-1.14193

used for smartphone covers

take it from the laboratory to the factory floor

expensive to make in large sheets

when made in large sheets, the properties are compromised

Graphene flagship project



Author
George Dyre
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