Thinnest plates that can be manipulated by hand developed

Researchers, including one of Indian-origin, have developed the thinnest plates ever that can be picked up by hands and can spring back to original shape even after being bent and twisted.
The plates are thousands of times thinner than a sheet of paper and hundreds of times thinner than household cling wrap or aluminium foil, researchers said.
Like cling wrap, comparably thin materials immediately curl up on themselves and get stuck in deformed shapes if they are not stretched on a frame or backed by another material.
Being able to stay in shape without additional support would allow this material, and others designed on its principles, to be used in aviation and other structural applications where low weight is at a premium.

"Materials on the nanoscale are often much stronger than you'd expect, but they can be hard to use on the macroscale," said Igor Bargatin, professor at University of Pennsylvania School of Engineering in US.
"We've essentially created a freestanding plate that has nanoscale thickness but is big enough to be handled by hand. That hasn't been done before," said Bargatin.

Other atomically thin films like those made of graphene typically need to be stretched like a canvas in a frame, or even mounted on a backing, to prevent them from curling or clumping up on their own.
"The problem is that frames are heavy, making it impossible to use the intrinsically low weight of these ultra-thin films," Bargatin said.

"Our idea was to use corrugation instead of a frame. That means the structures we make are no longer completely planar, instead, they have a three-dimensional shape that looks like a honeycomb, but they are flat and contiguous and completely freestanding," he said.
"It's like an egg carton, but on the nanoscale," said Prashant Purohit, an associate professor at the university.
The researchers' plates are between 25 and 100 nanometres thick and are made of aluminium oxide, which is deposited one atomic layer at a time to achieve precise control of thickness and their distinctive honeycomb shape.
Once finished, the plates' corrugation provides enhanced stiffness. When held from one end, similarly thin films would readily bend or sag, while the honeycomb plates remain rigid.

This guards against the common flaw in un-patterned thin films, where they curl up on themselves.
The plates could be used to make wings for insect-inspired flying robots, or in other applications where the combination of ultra-low thickness and mechanical robustness is critical.
"The thinnest man-made wing material I know of is made by depositing a Mylar film on a frame, and it's about half a micron thick," said Bargatin.
"Our plates can be ten or more times thinner than that, and don't need a frame at all. As a result, they weigh as little as than a tenth of a gram per square metre," he said.

The research was published in the journal Nature Communications.