Shanghai, China – Graphene paper, with the ability to fold itself, could be used to create miniature robots to artificial muscles, a new study says.
Scientists from Donghua University in China experimented with a sheet of graphene paper, being 200 times stronger than steel by weight. By applying a certain amount of heat to the material, it folds itself into a device that can walk forward and backward, and also change directions.
How does the graphene fold itself? Scientists treated certain sections of the graphene paper, making them to naturally absorb particles of water out of the vapor from the atmosphere. So, when the graphene gets heated, the water is released, causing the shrink and bend of the material. As the heat stops, the process goes in the opposite way.
Using this method in a well-designed device, it could bring us objects such as the walking device, and an artificial hand with the ability to hold and grasp objects five times heavier than the hand itself. They determine the 3D form that the paper is going to fold to by altering the placement of the treated areas.
Changing people’s lives
Jiuke Mu, a Ph.D. student at the Donghua University and one of the material’s inventors, stated that their research could have major improvements on the developing of modern applications, such as micro-robots, tissue engineering, and artificial muscles, according to LiveScience.
He believes that, in the near future, this type of discovery could change people’s lives. He sets the example with smart clothing, saying that it could adapt to the body, its temperature, and even environmental changes to make the subject’s life more comfortable.
“Compared with other kinds of self-folding materials, the all-graphene-based structure is simpler, its response behavior is faster and the output is more efficient,” Mu said, according to LiveScience. “More importantly, its origami and walking behavior is remotely controlled.”
Active-polymers researching
The study of self-folding materials, such as active polymers -materials that convert other forms of energy into mechanical work- has been on the table for years. Nevertheless, the studies have been conducted in very fragile conditions, failing to prove its efficiency yet.
Taking that into account, Mu and his colleagues decided to make their devices entirely out of graphene, showing the device was 90 percent effective after being folded more than 500 times. Also, the material showed an energy-conversion rate of 1.8 percent -much more than the previous 1 percent achieved by other active polymers.
Although pure graphene can have a high cost, it also takes lots of time to be created, so scientists used graphene oxide (GO) to create their own paper. It is equally effective, and much cheaper -it costs $0.16 per gram. They constructed nanosheets using GO, first building blocks and then sheets, before taking off all the oxygen of the material.
Mu and his team believe that “There is still room for improvement in the energy-conversion efficiency.”
Also, they informed that they will continue to study this material, although they are going to experiment in nano-scales to analyze its possibilities.
Source: LiveScience