Rice University scientists create patterned graphene onto food, paper, cloth, cardboard
Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.
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. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.
The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.
The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.
“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny 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. “All that could be placed not on a separate tag on the food, but on the food itself.”
Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.
“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”
The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.
Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.
“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”
The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.
Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.
Learn more: Graphene on toast, anyone?
The Latest on: Laser-induced graphene
via Google News
The Latest on: Laser-induced graphene
- Rice University Researchers Continue Work with 3D Graphene Foam on September 21, 2018 at 9:14 pm
This technique is a continuation of the university’s innovative work from 2014, which resulted in the first production of laser-induced graphene, or LIG, which can be made at room temperature in macro... […]
- Graphene foam sculpted for energy storage and sensors on June 15, 2018 at 4:59 am
The project was carried out at the Tour Lab at Rice, which produced the world’s first laser-induced graphene in 2014. By burning plastic with a laser, it is possible to transform the surface of the pl... […]
- Edible Electronics? Lasers are Bringing "Super Material" Graphene to Everyday Surfaces on March 9, 2018 at 11:37 am
Back in 2014, Tour’s lab reported that by shining a laser on a type of plastic called polyimide, they converted the illuminated surface into graphene. They called the result laser induced graphene, or ... […]
- New graphene laser technique opens door for edible electronics on March 7, 2018 at 8:32 am
Several years ago, James M. Tour and colleagues heated the surface of an inexpensive plastic with a laser in air to create something called laser-induced graphene (LIG). LIG is a foam made out of tiny ... […]
- Graphene-based edible electronics will let you make cereal circuits on March 1, 2018 at 8:05 am
The project, which uses something called laser-induced graphene (LIG), is a process that creates a “foam made out of tiny cross-linked graphene flakes” that can carry electricity through carbon-rich p... […]
- Scientists Use Graphene to Create Edible Electronics on February 19, 2018 at 12:08 pm
The team’s laser-induced graphene (LIG) tags comprise only a few layers of single-atom-thick graphene, which is produced out of the materials already present in an object. “This is not ink,” said Tour ... […]
- Edible electronics are on the way on February 18, 2018 at 5:06 am
In 2011 they made graphene out of insects, waste and even Girl Scout cookies, using a different technique involving carbon deposition on copper foil. The team recently developed the new technique of l... […]
- Graphene on toast? Edible electronics could help shield you from food poisoning on February 15, 2018 at 2:33 pm
What chemist James Tour and his lab have been investigating are ways to laser graphene onto food for what may turn out to be the start of a revolution in “edible electronics.” This laser-induced graph... […]
- Graphene cartoons created in food using laser technique on February 14, 2018 at 8:08 am
Professor James Tour’s lab is responsible for developing laser-induced graphene (LIG); graphene etched onto surfaces as the material itself is converted into graphene – an atom-thick layer of carbon a... […]
via Bing News