A team of researchers has found that by infusing an application of graphene into many common materials, a number of interesting things happen.
The atom-thick ‘wonder material’ graphene comes in many forms, but one particular type of production method has been found to be very promising. In a paper published to ACS Nano, a team of researchers from Rice University in the US and Ben-Gurion University in Israel revealed how laser-induced graphene (LIG) – a flaky, foam version of the material – would be greatly improved when included as part of a composite.
Once LIG was infused with plastic, rubber, cement, wax or other materials, the resulting composites showed a wide variety of applications. These include wearable electronics, heat therapy, water treatment, anti-icing and de-icing work, creating antimicrobial surfaces, and even in making resistive random-access memory devices.
First developed in 2014, LIG is created when a commercial laser burns the surface of a sheet of polyimide plastic, with the resulting heat turning a sliver of the material into flakes of interconnected graphene. The one-step process made much more of the material, and at far less expense, than through traditional chemical vapour deposition.
Since then, its developers have expanded upon the concept to create LIG with wood and food, having last year created graphene foam for sculpting 3D objects.
“LIG is a great material, but it’s not mechanically robust,” said James Tour, co-author of the research. “You can bend it and flex it, but you can’t rub your hand across it. It’ll shear off.
“If you do what’s called a ‘Scotch tape test’ on it, lots of it gets removed. But when you put it into a composite structure, it really toughens up.”
To create the composites, the team either poured or hot-pressed a thin layer of the second material over LIG attached to polyimide. When the liquid hardened, they pulled the polyimide away from the back for reuse, leaving the embedded, connected graphene flakes behind.
Talking about the antibacterial properties in particular, Tour said that the 20-micron-thick layer of LIG proved to be more than adept at this task.