Physicists at Cornell University have managed to shrink the art of kirigami down to the nanoscale, working with graphene, a material that's just one atom thick. The research could lead to the creation of some of the tiniest machines mankind has ever seen.
We've seen a host of different uses for graphene over the last few years, including flexible displays, highly sensitive audio devices and even the world's thinnest light bulb. Now, Cornell researchers have turned the unique material towards kirigami, which is similar to origami, but allows for both the cutting and folding of material.
After first using a laser cutter to build paper models of proposed designs, the researchers moved down to the nanoscale, working to forge the designs in graphene. The material is strong, conductive and just one atom thick, but given its tiny scale, can be extremely sticky, making it difficult to manipulate into complex structures.
To combat this, the team suspended it in water and added surfactants – compounds that lower surface tension – to make the material more slippery, and easier to contort as desired. Tiny gold tabs were also attached to the graphene, designed to act as gripping points at each end of the shapes.
The researchers fabricated several different designs, including a soft spring that works like a flexible transistor. The forces required to bend the tiny spring are around equal to that exerted by a motor protein, meaning that it could be placed in the body, and particularly the brain, and used for remote sensing.
The team also tested the durability of the graphene kirigami by opening and closing a nanoscale hinge. After 10,000 repetitions, there were no signs of damage, with the material remaining intact and elastic.
"It's one thing to read about how strong graphene is; it's another thing entirely to crumple it up and watch it recover, or to stretch a spring dramatically without tearing the materials," says study author Melina Blees. "It's not every day that you get to develop a feel for a nanoscale material, the way an artist would."
The researchers published the results of their work in the journal Nature.
Source: Cornell University