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Handy graphene foam combos keep surfaces ice-free



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4, the lab of James Tour, chair in chemistry as well as a professor of computer science and materials science and nanoengineering at Rice University, first made LIG when it used a commercial laser to burn the surface of a thin sheet of common plastic, polyimide. The laser's are turned into sliver of material into flakes of interconnected graphene. The one-step process made much more of the material, and that less expense, than through traditional chemical vapor deposition.

Since then, the lab and others have expanded their investigation of LIG, even dropping the plastic to make it with wood and food. Last year, the researchers created graphene foam for sculpting 3D objects.

"LIG is a great material, but it's not mechanically robust," says Tour, coauthor of an overview of laser-induced graphene developments in the Accounts or Chemical Research journal last year

 laser induced graphene chart
Scientists have combined laser-induced graphene with a variety of materials to make robust composites for a variety of applications. (Credit: Tour Group / Rice)

"You can bend it and flex it, but you can't rub your hand across it. It's shear off. If you do what is 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 make the composites, the researchers 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 giants, leaving the embedded, connected graphene flakes behind.

Soft composites can be used for active electronics in flexible clothing, Tour says, while harder composites make excellent superhydrophobic ( water-avoiding materials. When a voltage is applied, the 20-micron-thick layer of LIG kills bacteria on the surface makes toughen versions of the material suitable for antibacterial applications.

Composites made with liquid additives are best at preserving LIG flakes' connectivity. In the lab, they heated quickly and reliably when researchers applied voltage. That should give the material potential use as a deicing or anti-icing coating, as a flexible heating pad for treating injuries, or in garments that heat up on demand.

“You just pour it in, and now you transfer all the Beautiful aspects of LIG into a material that's highly robust, "Tour says.

The research appears in ACS Nano . Additional coauthors are from Rice, the Korea Basic Science Institute, the Indian Institute of Technology Bombay, and Ben-Gurion University of the Negev in Israel. The Air Force Office of the United States-Israel Binary Science Foundation supported the research.

Source: Rice University

Original Study DOI: 10.1021 / acsnano.8b09626


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