A team of Chinese scientists from South China Normal University and Beihang University has used graphene to create an artificial gas detector that is as good as a dog's nose. Their work showed that the graphene-based nanoscrolls can mimic a dog's sensitive sniffer, which is lined with millions of tiny capillaries. Since the capillaries cover such a large surface area, they can detect smells at extremely low concentrations.
Drawing inspiration from the capillary structure, the researchers found a way to modify graphene with a polymer to make high-quality nanoscrolls. These nanoscrolls have a large surface area similarly to a dog's nose. They are stable at high temperatures, and are strong and durable.
Graphene-based nanoscrolls, which are nanosheets of graphene rolled up in continuous and uniform manner, can be difficult to manufacture, consume a lot of energy and difficult to scale up. Past studies have used raw graphene or modified graphene that either left behind some unrolled structures, or shriveled up and aggregated, respectively.
The team prepared graphene-based nanoscrolls with the addition of poly or sodium-p-stryrenesulfonate, using the freeze-drying method to create uniform, unaggregated structures. It showed that the nanoscrolls had a wide, tubular shape, and almost all of the graphene was rolled up. The researchers then incorporated the nanoscrolls into a gas sensor, which was highly selective and sensitive. They said that this method had the potential for large-scale production.