Graphene: 21st century wonder material
CAPE TOWN – Over the past millennia technological advances have to a large extent determined the course of civilisation and even history. Bronze and iron were so crucial in the history and development of ancient societies that retrospectively whole eras were named after them such as the bronze and iron ages.
During the Bronze Age (≈3300-1200 BC) it was the production of the harder and more durable bronze through the smelting of copper and adding of tin or arsenic that gave civilisations a technological advantage.
In the Iron Age (≈1200-600 BC) iron and steel were introduced and people started to make tools and weapons superior to their bronze equivalents. Iron tools made farming much easier and superior iron weaponry also allowed the Persians to establish the first Persian Empire, which became one of the largest empires in history, extending from the Balkans of Eastern Europe to the Indus Valley in India.
With the rise of the European and American steel industry railroad tracks were spreading and enhanced transport and trade. Silicon semiconductors enabled the building of computers, which is one of the greatest technological innovations since the Gutenberg printing press of 1450.
All the above technologies moulded the development of society, and contributed to their economic power and global domination.
Change the future
Now, a new material has the potential to change the future as in the case of history past. This material is graphene and was briefly mentioned in Tech News last Friday when its use in smart contact lenses was described.
Graphene is widely called a “super material” and its remarkable characteristics could have far-reaching implications for the future of physics, engineering, bioengineering and civilisation as a whole. Graphene is stronger than steel, thinner than paper and could very much be the technology that changes the course of history in the 21st century.
Graphene is considered one of the disruptive technologies of the Fourth Industrial Revolution (4IR) and could lead to numerous innovations that open up new markets and replace existing technologies or materials. It is purported to transform everything from computing and car tyres to solar cells and smoke detectors. When graphene is used both to improve an existing material and in a transformational capacity its true potential is realised.
But what precisely is this promising graphene? Graphene is a monolayer or single, thin layer of graphite (the soft, flaky material that is used in the lead of a pencil) in the form of a two-dimensional, atomic-scale, hexagonal lattice (with a honeycomb-like appearance) in which one atom forms each vertex. Interestingly, every pencil mark contains a tiny speck of graphene, but since they are only one atom high, we cannot see them.
Graphite is an allotrope of carbon and thus possesses the same atoms as carbon, but they are arranged in a different way, assigning different properties to the material. Graphite consists of bonded layers of atoms that are very weakly held together by Van Der Waals forces (weak, short-range electrostatic attractive forces between uncharged molecules).
Radically different characteristics
Diamonds and graphite are both made of identical carbon atoms, but their characteristics are radically different since the atoms are arranged in completely different ways. In diamonds the atoms are tightly bonded in three-dimensional tetrahedrons (or triangular pyramids), whereas in graphite, atoms are bonded tightly in two-dimensional layers held together by weak forces. It is this arrangement of atoms that give the two materials their different properties: graphite is black, dull and relatively soft, while diamonds are transparent and one of the hardest natural materials.
In the last few years scientists have discovered several other allotropes of carbon with very interesting properties. Fullerenes or hollow cages of atoms, for instance, were discovered in 1985, including the so-called Buckyball. Others are nanotubes (flat sheets of carbon atoms curled into exceptionally thin, hollow tubes of one nanometre in diameter) and graphene.
What makes graphene unique is that when it is isolated from graphite it is a mere one-atom thick with a molecular bond length of 0.142 nanometres. A stack of about 3 million layers is needed to make graphene of 1mm thick. Graphene is the first two-dimensional material ever discovered and is one million times thinner than the diameter of a single human hair. Although graphene is the thinnest material known to man (1 square meter only weighs around 0.77 milligrams), it is between 100-300 times stronger than steel and one of the strongest materials in the known universe - yet incredibly lightweight and flexible. The structural and physical characteristics of graphene make the potential applications in a variety of technological fields very promising.
Interesting is that graphite has been used by humans since the Neolithic era. However, Andre Geim and Konstantin Novoselov from the University of Manchester only discovered graphene by accident in 2004 through the use of scotch tape!
Thin flakes on tape
While polishing a large block of graphite with scotch tape, the researchers discovered extremely thin flakes on the tape held together by van der Waals forces. After peeling super-thin layers of one atom each from the graphite flakes, they found graphene. However, the scientific world was very sceptical and their paper has been rejected twice by the prestigious journal, Nature. It was only much later that Geim and Novoselov’s paper was published. In 2010 the Nobel Prize for Physics were awarded to them for their discovery of this remarkable and exciting material.
But graphene has many more distinctive characteristics than its thinness and strength. It is thermally (the best conductor of heat at room temperature) and electrically conductive, while still transparent. It is magnetic, has a uniform absorption of light across the visible and near-infrared parts of the spectrum, and apparently impermeable to most liquids and gases.
Since carbon is the chemical basis for all known life on earth (2nd most abundant mass within the human body and the 4th most abundant element in the universe), graphene is an eco-friendly, sustainable solution for an almost infinite number of applications.
It is this incredible breadth of properties that allows graphene to play a significant role in a vast number of products, processes and industries. No other material has the same breadth of properties that graphene boasts, making it ideal for countless applications. This has made graphene the object of research by numerous scientists in fields varying from consumer technology to environmental science. Particularly in transport, medicine, electronics, energy, defence, and desalination, to name a few, graphene research is making a substantial impact. It seems as if the potential of graphene is limited only by our imagination.
A wonderful material
But if graphene is such a wonderful material, why do we not find it everywhere? As is often the case with new materials, graphene is still extremely expensive to produce in large quantities, limiting at the moment its use in any product that would demand mass production.
But graphene research is by no means slowing down. Researchers the world over — including the University of Manchester, where graphene was first discovered — are continually filing patents for new methods of creating and using graphene. The European Union invested heavily in research into the use of graphene in electronics, as well as many major tech companies in Asia such as Samsung.
Graphene could easily become a battlefield in international power play in the coming years. Empires during history often rose and fell based on their control of resources such as bronze, iron and steel.
Revolutions do not happen overnight. Silicon was discovered in the mid-19th century, but it took nearly a century before silicon semiconductors paved the way for the rise of computers. Perhaps graphene, with its almost mythical qualities, will become the resource that drives the next era of human history.
Professor Louis C H Fourie is a futurist and technology strategist. [email protected]
BUSINESS REPORT ONLINE