Material science could be ranked as one of the significant factors for advances in technology in the history of humans. The human innovativeness was responsible for discovering or synthesizing consequently advanced and improved materials throughout, ever since the discovery of fire. From the Bronze age to the industrial revolution a couple of centuries ago, the level of human technology has increased noticeably. However, the substantial advances in material science have been possible within the last century and the current one.
Thanks to innovations and advances in other technological fields, especially electronics and nano-technology. We have been able to synthesize materials, which were only part of theories and folklore. Graphene is one such revolutionizing material which has discovered more recently.
Let’s learn a little about the wonder that is graphene and then discover its derivative graphene oxide to know its properties and applications.
What is Graphene?
Graphene is a form (allotrope) of carbon with a unique physical molecular structure which gives it genuinely amazing properties. Graphene material is composed of carbon atoms that arranged in a perfect honeycomb-like design. Graphene is a single-atom-thick sheet of carbon atoms that linked with three closest carbon atoms with a special sp2-hybridized electron bond.
This typical structural design gives graphene immensely wonderful and unique properties that are not noticed in any other material known to us.
The best aspects of graphene are that despite being only 1-atom thick, it is known to be the most substantial material known to man, 100 times stronger than the most durable industrial steel created and many times tougher than original diamond. Graphene is also extremely conductive of electricity and heat, as every carbon atom within it has 1 electron free to move quickly over the entire surface of the sheet of graphene.
As it is only 1-atom thick, graphene is also one of the lightest, most flexible and completely transparent materials today. These impressive properties allow numerous potential and current applications of graphene in various industries, such as aeronautics, material technology, photovoltaic energy storage, electronics, medicine, and many more.
Today, scientists have been able to use graphene as the base and synthesize several other incredible materials, including graphene oxide. Graphite is one such material which developed by stacking sheets of graphene one atop the other. Rolling graphene sheets gives carbon nanotubes (CNTs).
What is Graphene Oxide?
Graphene, although an excellent and advantageous material, is quite expensive and requires an exhaustive, careful process to be synthesized. Hence, scientists after the discovery of graphene in 2003 have been intensely studying ways to develop similar materials more efficiently and inexpensively.
One such easy-to-derive material from graphene is Graphene Oxide (GO). Graphene oxide is also single-layer thick and derived after putting the considerable abundant graphite through a rigorous oxidation process. Graphene oxide is an intensely-oxidized form of graphene itself and has sufficient oxygen-containing groups within it.
Graphene oxide is considered an ideal alternative to graphene as it is water-soluble and can also disperse in many other industrial solvents. Besides, GO is also excellent for use in synthesizing graphene.
Although graphene oxide does not show the electric-conducting properties like the impressive graphene various studies have proven its conductivity and other properties.
Currently, you can get graphene oxide as a substrate, coating, in dissolved/dispersed form or even in a powdered form.
How is Graphene Oxide made?
Graphene oxide is today derived using one of the four most popular methods, namely:
- Hoffman Method
- Hummers Method
- Staudenmaier Method
- Brodie Method
Although there are several variations of these processes today these are in pursuit of finding better, improved and even cheaper ways to produce graphene oxide. Each of these GO-derivative methods is evaluated according to the ratio of carbon to oxygen they provide in the finished product.
What are the Properties of Graphene Oxide?
These are the specific properties of graphene oxide which makes it another wonderful and useful material to us today:
- Oxygen (O) – 70.5%
- Carbon (C) – 23%
- Hydrogen (H) – 1.2%
- Sulfur (S) – 0.4%
- Nitrogen (N) – 4.9%
- Linear Formula – CxOyHz
- Thickness – 3 nm – 5 nm
- Color – Grayish-Black
- Purity – >99%
- Bulk Density – 0.48 grams/cubic cm
- Surface BET Area – >110 sq. m/gram
- Lateral Dimension – 5 micron – 10 micron
What are the Applications of Graphene Oxide?
Thanks to its unique properties and chemical structure, graphene oxide is finding ever-increasing use in numerous processes within varied industries.
These are some of the potential and current applications of graphene oxide in material science R&D (academic and commercial studies)
- Energy and Power industry
- Defense labs
- Biomedical procedures
- LED technology
- Super-capacitor material
- Solar cell development
- Aeronautical industry
Graphene oxide has significant electronic, thermal and physical properties which makes it an excellent product for use in not only research and development of advanced materials, but also in revolutionizing the energy storage industry as well.