The self-healing properties of skin — the human body’s largest organ — has long been a source of fascination and frustration because in spite of numerous studies, man has yet to discover or invent a material that can emulate this amazing property. Now, with graphene in the picture, this status quo might soon change.
Graphene, basically a single sheet of pure carbon atoms bonded together in hexagonal form, is currently considered as the world’s strongest and thinnest material. It is only one atom thick (which means it’s a million times thinner than a sheet of paper) that it is considered as a two-dimensional material, the first of its kind ever.
The discovery of graphene has caused quite a stir because it exhibits several features that can only be described as extraordinary (others even describe it as ‘magical’), thus earning for itself the distinction of being a ‘supermaterial’ and a ‘wonder material’. For starters, in spite of its thinness, it is over 100 times stronger than steel and virtually impenetrable. It’s a superconductor — it is an excellent conductor of both heat and electricity. It is transparent and highly flexible. It also has remarkable light absorption properties.
With all these features, a lot of industries — from computer and electronics, to medicine, hygiene and environmental science — are bound to benefit from its applications. And with recent discoveries showing that it might soon be possible to mass-produce graphene at a low cost, its potential applications have widened even more.
As if all this wasn’t enough, a research team at the Indian Institute of Technology at Hyderabad, India led by Dr. Swati Ghosh Acharyya recently uncovered another astounding property of graphene — self-healing. And so we now have a material that can potentially be developed into flexible sensors that can mimic what the human skin can do. With this, we may soon have robots with skin just like ours.
To arrive at their results, the team set out to observe the self-healing behavior of pristine and defective graphene. As Dr. Acharyya told Newswise: “We wanted to observe the self-healing behavior of both pristine and defected single layer graphene and its application in sub-nano sensors for crack spotting by using molecular dynamic simulation.”
To do this, they subjected graphene with different kinds of defects to a form of stress (they refer to it as ‘uniaxial tensile loading’) until it fractured. When the ‘load’ was relaxed, the graphene began to heal itself. And this behavior was the same, as long as the crack was within a defined threshold (0.3-to-0.5 nanometers). Supposedly, self-healing happened through ‘spontaneous recombination of dangling bonds’.
If this self-healing behavior can be replicated in artificial skin, we can be looking at a wide range of practical applications such as sensors, mobile gadgets and ultracapacitors. And that’s on top of graphene’s potential use in solar power generation, water filtration, medical diagnosis, bionic devices, spacecraft building and carbon dioxide conversion. And the list just keeps on growing. A wonder material indeed.
The discovery has been published in the journal Open Physics.