Graphene is a two-dimensional sheet of carbon atoms arranged in a hexagonal lattice with many desirable mechanical properties, including extreme strength and stretchability. However, manufacturing graphene is typically expensive and time-consuming.
Graphene oxide is a much more affordable alternative to graphene with similar mechanical properties. Graphene oxide is graphene covered with oxygen and hydrogen groups; it is what becomes of graphene that is left out in open air.
Researchers at MIT and Harvard created graphene oxide nanoscrolls by stimulating flakes of graphene oxide in solution with both low and high frequencies. The low-frequency method used a tip-sonicator to produce sound waves at 20 Hz when placed in the solution, while the high-frequency method used a custom reactor that shook the solution at 390 Hz.
A Cheaper Alternative to Pure Graphene
Although only about 10 percent of the graphene flakes were successfully turned into scrolls in the initial experiments, the researchers are optimistic about the potential for optimization. If scaled up, the process could be compatible with current industrial processes and would allow for the production of bulk samples of cheap water filters.
“If you really want to make an engineering structure, at this point it’s not practical to use graphene,” said Itai Stein, a graduate student in MIT’s department of mechanical engineering. “Graphene oxide is two to four orders of magnitude cheaper and with our technique, we can tune the dimensions of these architectures and open a window to industry.”
Tuning the dimensions of the nanoscrolls could enable them to trap specific pollutants. Stacking billions of them together could create a strong and lightweight water purification membrane. Nanoscrolls also have the potential to be used as ultralight chemical sensors, drug delivery vehicles and hydrogen storage platforms.
Stein and Carlo Amadei, a graduate student at Harvard, have published the results of their research in the journal Nanoscale.