In the Spotlight: Graphene Platelets
The 15-year-old supermaterial graphene is back in news, now in a slim and trim form
Strong stuff
The 2010 Nobel Prize in physics was awarded to University of Manchester scientists Andre Geim and Konstantin Novoselov for their pioneering research on graphene, a one-atom-thick film of carbon whose strength, flexibility and electrical conductivity make it a super material of the century. It could hold the key to everything from super small computers to high-capacity batteries. Graphene’s properties make it possible to build circuits that are smaller and faster than what you can build in silicon. Scientists are keen on unravelling more powers of this wonder substance.
Meet the researchers:
Prof Sathyan Subbiah and Wazeem Nishad of Indian Institute of Technology Madras in their recent article have shown a simple route to producing graphene platelets from graphite.
“They have found that when graphite is suspended in an appropriate fluid and subjected to an intense shearing force of machining, the layers of graphite separate into graphene platelets.”
Graphene is the building block of the more commonly known graphite; a one millimetre-thick sheet of graphite is made of 3 million layers of graphene. Superior quality graphene is frequently prepared by the exfoliation method,” said Subbiah. Exfoliation is a top-down approach of synthesis that involves breaking the weak forces of attraction between the layers using external energy like electrical, chemical, thermal or mechanical.
How did they do it?
Graphite is a lubricant because it is made of layers of carbon that slide over one another. The lubricating action itself would shear the layers off, and cause separation of the 2-D graphene sheets. This way of looking at exfoliation from an unconventional angle was what led to the development. They suspended graphite in a lubricant liquid containing sodium cholate to prevent the graphite particles from clumping together and subjected the suspension to the machining of mild steel using oscillations of a carbide tool. Intermittent cutting by oscillating the tool allowed the entry of the graphene flakes. From a few graphene layers having a thickness ranging between 1 and 4 nm to multilayer graphene flakes with a lateral dimension less than 100 nm, these graphene nanoplatelets are about to revolutionise technology.
The Takeaway:
Graphene’s conductivity and mechanical strength for use as an electrode material is its key commercial application. It can serve as a flexible replacement for indium-tin-oxide as a transparent conductive electrode for touch-screen displays, for example.
We are eagerly waiting for sleeker and smarter foldable technology, soon becoming a reality thanks to efficient ways to produce graphene nanoplatelets!
Jasmine Jerry is a third-year undergraduate pursuing Aerospace Engineering passionate about robotics and unmanned systems. She spends most of her time on soccer-playing robots or aerial vehicles. She also is a member of Lean In Chapter at IIT Kharagpur.
