If graphene is to go mainstream, it needs to be mass-produced, which is where a new breakthrough from MIT comes in.
The word graphene is enough to stoke the interest of anyone working in the materials science space but, since its discovery at the beginning of the millennium, its use has rarely left the lab.
This is because, even though the atom-thick layer of graphite promises ultra-conductivity and flexibility for a multitude of different uses, it is very expensive to produce.
However, a recent breakthrough achieved by a team from MIT could help us break through the cost barrier, similar to what we have today in the production of aluminium.
According to MIT News, the team has demonstrated a continuous manufacturing process that produces long strips of high-quality graphene.
This would make it the first demonstration of an industrial, scalable method for manufacturing high-quality graphene tailored for use in membranes using a variety of molecules including salts, larger ions, proteins or nanoparticles.
Pinpointing what uses such a manufacturing method could have, the team said it would be ideal for desalination and biological separation in particular, but not limited to those.
To achieve the breakthrough, the team led by the director of the Laboratory for Manufacturing and Productivity at MIT, John Hart, turned to a common industrial manufacturing process for thin foils, known as the roll-to-roll approach.
This is then combined with the common graphene fabrication technique of chemical vapour deposition, whereby copper foil is fed into a heated tube before mixing with methane and hydrogen gas, creating a layer of graphene foil.
‘Like a continuous bed of pizza’
“Graphene starts forming in little islands, and then those islands grow together to form a continuous sheet,” Hart said.
“By the time it’s out of the oven, the graphene should be fully covering the foil in one layer, kind of like a continuous bed of pizza.”
The results of the experiments showed that the process could produce graphene at 5cm per minute, with its longest run lasting for almost four hours, producing 10 metres of continuous graphene.
Hart added that if it were running in a factory 24/7, it would be able to essentially create a printing press of the so-called wonder material.
The next step is to see how the team can include polymer casting, as well as other methods that are currently performed by hand, in the roll-to-roll system.
“For now, we’ve demonstrated that this process can be scaled up, and we hope this increases confidence and interest in graphene-based membrane technologies, and provides a pathway to commercialisation,” he said.