To do this, a team led by Rice chemist James Tour used an industrial laser to blacken a thin film pattern onto a block of pine. The specific pattern is something called laser-induced graphene (LIG), a method for creating flexible, patterned sheets of multilayer graphene without the need for hot furnaces and controlled environments. It was discovered at Rice in 2014, but was initially applied only to sheets of inexpensive plastic called polyimide. This marks the first time the technique has been applied to wood. Pine works as a substitute for polyimide because of a similar mechanical structure, courtesy of an organic polymer called lignin.
The LIG process (or, in this case, pine laser-induced graphene, aka P-LIG) is carried out in an inert argon or hydrogen atmosphere. The lack of oxygen means the heat from the laser does not burn the pine, but instead transforms its surface into wrinkled flakes of graphene foam bound onto the wood’s surface. Following experimentation, 70 percent power was discovered to be the optimal amount of laser power to produce the highest-quality graphene possible.
Compared with polyimide, the advantage of turning wood into graphene is that wood is an abundant and renewable resource. Given the astonishing number of potential applications for graphene– from highlighting structural defects in buildings to creating new types of speakers to, yes, detecting cancer — this could prove to be a significant breakthrough.
For now, however, it seems the main application the Rice researchers are interested in relates to electronics. Specifically, they are hoping to harness the conductive properties of the pine laser-induced graphene to create supercapacitors for energy storage. With the massive amount of electronic waste that is produced every year, the idea of biodegradable, eco-friendly wooden electronics carries obvious benefits. When the project gets a little further down the line, someone needs to hook the Rice researchers up with these hardwood PC makers, stat!
A paper describing Rice University’s research was recently published in the academic journal Advanced Materials.
