Fourteen years ago, Nobel prize winners Andre Geim and Konstantin Novoselov created one of the strongest materials in the world using just some graphite and scotch tape. Graphene is one of the thinnest materials ever made, but is still hundreds of times stronger than steel. It is as pliable as rubber and an excellent electrical conductor. When news about graphene first came out, scientists proposed myriad uses of the material from creating electronics to developing new water purification technologies. But graphene hasn’t lived up to the hype it initially created. This raises an important question: Why is graphene not ubiquitous in today’s world?
A visual representation of the structure of graphene. Image Source: SketchPort by User magicalhobo (2014)
Graphene has a unique structure that gives it many desirable characteristics. It is composed of only a single layer of carbon atoms arranged in interlocking hexagons, much like chicken wire. Scientists from Northwestern University have exploited this property in an atypical application – Using graphene as a hair dye alternative. Graphene is mixed with chitosan, a sugar from crustacean shells, and applied onto the hair. Graphene wraps around the hair follicles and the chitosan glues it into place, allowing the dye to stay on even after 30 washes. The findings are significant because the treatment does not cause any hair damage, unlike typical hair dyes which use chemical reactions to change hair colour.
A vintage advertisement for a chemical hair dye proclaiming to preserve natural hair colour. Image Source: Flickr by User Classic Film (2015)
In a more radical application, graphene could be used to make artificial heart valves. Heart valves are attractive sites for clot formation after surgery. These clots can block blood vessels, eventually resulting in death. Patients thus need to take anticoagulant drugs for life to prevent such clots from forming. Instead, scientists from two U.S. universities suggest coating the heart valve itself with a catalyst that produces the needed anticoagulant. Graphene could be used as a durable scaffold for this catalyst, eliminating the need for a lifetime course of medication.
Visual representation of a blood clot. The thrombus/blood clot obstructs the flow of blood through the vessel. Image Source: Wikipedia by User Persian Poet Gal (2006)
However, graphene yet has to overcome many obstacles before it can be put to practical use. The biggest hurdle remains how we make graphene on a large scale. It is difficult to control the structure of graphene when it is manufactured as large sheets. This problem arises from the structure of the material itself – Because graphene is very thin, it is difficult to handle in large volumes. Even if this problem is solved, we must consider the overall cost of producing graphene. At present, graphene production requires the use of extreme reaction conditions such as high temperatures and low vacuum environments. Graphene is simply not cost effective for its proposed uses.
In the long run, it is also important to consider some of the health and environmental concerns of using graphene. These influences are difficult to predict for a material that is only starting to come into use, but several studies have already begun to focus on the potential toxicity of graphene. A study published in 2016 revealed that inhaling high doses of graphene oxide could result in lung damage in humans. The findings are particularly significant when considering the applications of graphene in products such as hair dyes. Accidentally inhaling or ingesting a hair dye could result in significant health concerns. It is then also important to investigate the effects of graphene on other flora and fauna. The results from such studies could influence how we dispose of graphene in the environment.
From my viewpoint, these predicaments are not unusual for many innovative technologies. The process of translating scientific discoveries from the lab bench-top into a commercially viable product is often difficult and suffers from a significant lag time. While it would be nice for these potential applications to materialize, we should act in a prudent manner. The long-term impacts of graphene on human health and the environment are important to consider before we start to use graphene more widely. My two cents would be to consider the problem one layer at a time.
