Could This Little Strip of Graphene Foam Be the Next Explosive Detector?

It’s the size of a postage stamp, only one layer of atoms thick and 10 times more effective at sensing chemicals in the air than the commercial sensors used today.

Meet the graphene foam created by researchers at Rensselaer Polytechnic Institute in New York. As Popular Science states, it’s rare that we hear of nanotechnology that has direct applicability today — often times it’s still too futuristic, however cool.

Graphene foam. (Photo: Nikhil Koratkar via RPI)

Popular Science reports how this technology is an improvement over traditional chemical sensors:

The new sensor dispenses with a lot of the limitations that have been holding back sensors in this space. In the last several years, many strides have been made in the science of manipulating nanostructures to be excellent detectors of very fine trace elements of chemicals on the air. But these sensors, while great in theory, are impractical in actual service.

Current sensor designs are complex, often relying on an individual nanostructure that must be carefully manipulated and even more carefully analyzed. They are often not reusable and must be deployed at specific temperatures or pressures, making a handheld sensor device unreliable, very expensive, and impossible to use repeatedly.

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When exposed to air, particles adsorb to the foam’s surface. And each of these particles affects the graphene foam in a different way, slightly modifying its electrical resistance. Run a current through it, and a measurement of the change in resistance tells a you what’s sticking to the foam. Moreover, by running a roughy 100-milliampere current through the foam the RPI team found they could cause the particles to desorb–that is, they unattached themselves from the sensor, cleansing it so it can be used again and again.

Close-up of grapheme foam. (Photo: Nikhil Koratkar via RPI)

Here’s an explanation from one of the researchers, Nikhil Koratkar, of how the foam was developed and how it works:

Popular Science reports that when the foam is engineered to sense chemicals like ammonia, which is found in homemade explosive devices, it can detect particles at 1,000 parts-per-million within five-to-10 minutes.

“In a sense we have overcome the Achilles’ heel of nanotechnology for chemical sensing,” Koratkar said on RPI’s website. “A single nanostructure works great, but doesn’t mean much when applied in a real device in the real world. When you try to scale it up to macroscale proportions, the interfaces defeats what you’re trying to accomplish, as the nanostructure’s properties are dominated by interfaces. Now we’re able to scale up graphene in a way that the interfaces are not present. This allows us to take advantage of the intrinsic properties of the nanostructure, yet work with a macroscopic structure that gives us repeatability, reliability, and robustness, but shows similar sensitivity to gas adsorbtion as a single nanostructure.”