The researchers'
plates are strong enough to be picked up by hand and retain
their shape after
being bent and squeezed.
(December 5, 2015) Scientists
and engineers are engaged in a global race to make new materials that are as
thin, light and strong as possible. These properties can be achieved by
designing materials at the atomic level, but they are only useful if they can
leave the carefully controlled conditions of a lab.
Researchers at the University of Pennsylvania have now
created the thinnest plates that can be picked up and manipulated by hand.
Despite being thousands of times thinner than a sheet of
paper and hundreds of times thinner than household cling wrap or aluminum foil,
their corrugated plates of aluminum oxide spring back to their original shape
after being bent and twisted.
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.
The hexagonal
corrugation of the plates is responsible
for their
stiffness and strength.
The study was led by Igor Bargatin, the Class of 1965 Term
Assistant Professor of Mechanical Engineering and Applied Mechanics in Penn’s
School of Engineering and Applied Science, along with lab member Keivan Davami,
a postdoctoral scholar, and Prashant Purohit, an associate professor of
mechanical engineering. Bargatin lab members John Cortes and Chen Lin, both
graduate students; Lin Zhao, a former student in Engineering’s nanotechnology
master’s program; and Eric Lu and Drew Lilley, undergraduate students in the
Vagelos Integrated Program in Energy Research, also contributed to the
research.
They published their findings in the journal Nature
Communications.
“Materials on the nanoscale are often much stronger than
you’d expect, but they can be hard to use on the macroscale” Bargatin said.
“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.”