Graphene on Toast

Spring 2018
By Mike WIlliams

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.” The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene (LIG) can be burned into paper, cardboard, cloth, coal and certain foods — even toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny radio-frequency identification (RFID) tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin, and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing,” he said, “whether you want to heat the clothing or add a sensor or conductive pattern.” The Air Force Office of Scientific Research supported the research.