One of the single most promising materials currently known to man could be produced by a kindergartener. Nobel laureate Andre Geim and his team discovered as much with Scotch tape and a simple slab of graphite. When the scientists placed and removed tape from the graphite slab, layers of graphite stuck to the tape. By folding the tape and pressing, they were able to peel the graphite into smaller layers. Geim’s team used this “Scotch tape method” to create the first ever sample of graphene (1).
Graphene is a single layer of carbon atoms arranged in a hexagonal pattern, and is most easily created through the separation of pyrolytic graphite layers. Pyrolytic graphite is nearly identical to natural graphite but with more easily separable graphene layers (2). Because of graphene’s hexagonal structure, each carbon atom is covalently bonded to 3 others, which leaves one electron per atom free. When an electrical current is run through graphene, these free electrons can move above and below the sheet with barely any resistance or energy loss (3). In fact, graphene nanotubes have been shown to carry a maximum electrical current approximately 1000 times greater than that of the copper, the most commonly used wiring material (4). Graphene is also incredibly strong, with a tensile strength (resistance to tension) 100 times greater than that of the strongest steel (5). With such attractive properties, graphene gives humans the potential to create faster computers, stronger buildings, more precise medical equipment, longer-lasting batteries, and so much more. It’s no wonder that graphene has become a buzzword in the scientific zeitgeist.
However, a simple search for graphene products won’t yield groundbreaking new technologies; rather, sportswear and simple electronics. Why is this? As engineers and material scientists have come to discover, integrating graphene into modern technologies is no small task. Commercial graphene is generally produced in the form of graphene nanoplatelets (GNPs) or sheets, both of which come with unique shortcomings. Synthesizing GNPs requires graphite blocks to be exfoliated in strong acids and oxidants that lead to structural imperfections in the final product -- thus limiting GNPs’ viability as a material for precise equipment. Continuous graphene sheets are less flawed than their GNP counterparts, but production requires significantly tighter control and imposes a steep financial burden on producers (6). Another problem for scientists is that graphene, while being strong, is not very tough. Strength measures a material’s resistance to deformation, while toughness measures its resistance to fracture. To the dismay of engineers everywhere, Graphene’s toughness was found to be barely greater than that of normal graphite (7). The combination of imperfect mass production techniques and brittleness have left graphene in a state of limbo: scientists recognize its potential, but are unable to capitalize upon it.
While this stagnation may somewhat lessen graphene’s initial allure, there is a historical precedent for just this situation: plastics. Celluloid plastic was initially created in 1869 as a substitute for ivory and received widespread attention for its remarkable properties (8). Yet much like graphene today, celluloid maintained a modest role in the material world as it was difficult to work with. It wasn’t until the beginning of World War 2 that plastics experienced an overhaul: new polymers were discovered and production ramped up. People found uses for plastic in almost every facet of life (9).
Engineers and inventors will continue to lag behind their scientific counterparts for decades before they are able to properly produce and handle graphene on a commercial level even close to that of plastic. They may never reach that level at all. Even so, graphene’s impressive and undeniable potential makes it a material worth following.
References:
- Colapinto, J. (2014, December 15). Material Question. Retrieved from https://www.newyorker.com/magazine/2014/12/22/material-question
- Randviir, E. P., Brownson, D. A., & Banks, C. E. (2014). A decade of graphene research: Production, applications and outlook. Materials Today, 17(9), 426-432. doi:10.1016/j.mattod.2014.06.001
- Malik, R., Tomer, V. K., & Chaudhary, V. (2019). Hybridized Graphene for Chemical Sensing. Functionalized Graphene Nanocomposites and Their Derivatives, 323-338. doi:10.1016/b978-0-12-814548-7.00016-7
- Georgia Institute of Technology. (2009, August 15). Graphene Has High Current Capacity, Thermal Conductivity. ScienceDaily. Retrieved from www.sciencedaily.com/releases/2009/07/090729210454.htm
- Lee, C., Wei, X., Kysar, J. W., & Hone, J. (2008). Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene. Science, 321(5887), 385-388. doi:10.1126/science.1157996
- Kong, W., Kum, H., Bae, S., Shim, J., Kim, H., Kong, L., . . . Kim, J. (2019). Path towards graphene commercialization from lab to market. Nature Nanotechnology, 14(10), 927-938. doi:10.1038/s41565-019-0555-2
- Chao, J. (2016, February 12). Graphene is Strong, But Is It Tough? Retrieved from https://newscenter.lbl.gov/2016/02/08/graphene-is-strong-but-is-it-tough
- Knight, L. (2014, May 17). A brief history of plastics, natural and synthetic. Retrieved from https://www.bbc.com/news/magazine-27442625
- Freinkel, S. (2011, May 29). A Brief History of Plastic's Conquest of the World. Retrieved from https://www.scientificamerican.com/article/a-brief-history-of-plastic-world-conquest/