A new study suggests that self-folding graphene paper may be used in the future to create various things from artificial muscles to miniature robots.
Researchers from Donghua University in China found that heating a sheet of graphene paper (which is between 100 and 300 times stronger than steel) can make it fold into a device that has the ability to walk.
Jiuke Mu, a Ph.D. student at Donghua University who was involved in the new project, said that these devices that can fold themselves could be used for modern applications, such as tissue engineering, artificial muscles, micro robots, and so on.
This new technology could change people’s lives in the future. For instance, scientists are working on smart clothing, which changes its style and shape in response to environmental changes, body temperature, and other factors of this sort, Mu said.
How the technology works is that the graphene paper has specially treated sections that can absorb water vapours directly from the atmosphere. When the graphene paper is gently heated, the water dries up, making those sections bend and shrink. The process is reversed once the heating stops.
A good placement of the specially treated sections made it possible for scientists to build a self-assembling box, a walking device, and an artificial hand.
In recent years, self-folding materials have caught the attention of researchers. In their studies they focused on electro-active polymers (EAPs) – which are able to turn other forms of energy into mechanical work.
Mu and his colleagues created the device entirely out of graphene, which increased its resistance, making it 90 percent effective even the 500th time it got folded.
Because pure graphene can be quite expensive and it takes a lot of time to create, the scientists made the graphene paper using graphene oxide (GO). According to Mu, graphene oxide costs about 1 Yuan (which equates to 16 U.S. cents).
Some areas of the graphene oxide paper were treated with polydopamine (PDA) – a polymer used for coating various surfaces – to prevent them from being reduces once the scientists started carrying out the reduction reaction.
The findings of the study were published November 6 in the journal Science Advances.