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Ultrathin but super strong

  • Principal Investigator: Heinrich Jaeger, PhD, Physics Professor; the James Franck Institute Professor; and Director of the Materials Research Science and Engineering Center at the University of Chicago
  • Amount: $405,000
  • Source: National Science Foundation ARRA Funding
  • Goal: Test the properties of a new class of ultrathin nanoparticle sheets created at The University of Chicago


Jaeger and his colleagues have assembled what he jokingly calls "the world’s smallest trampoline" to study the properties of a new, ultrathin, stretchy material they fabricate in their lab.

After poking sheets of the material with tiny needles and bouncing things on them, the researchers have been amazed by the strength and flexibility of the material, especially considering it is only one nanometer thin. That’s one billionth of a meter!

"This material is turning out to be remarkably stronger than current predictions said it would be," says Jaeger, who created this new class of ultrathin nanoparticle sheets.

The composition of the material could be envisioned as coins laid out on a table—except that the gold, silver, copper or other metallic particles that make up these sheets are 1 nanometer thick and 5-10 nanometers wide. Each metallic particle is coated with an ultrathin layer of organic oil-like molecules.

The material holds together in sheets that are hundreds, even thousands of nanoparticles wide, which allows it to be stretched like cellophane over an opening. And since there are tiny spaces between the particles, the sheets can be used as membranes, or molecular sieves. Varying the type and dimension of the particles and the size of the spaces between them changes the permeability of the material.

The material can also be used to coat things; to reflect laser beams between mirrors in laser cavities; in micro-electronics; and in other research applications. A particularly exciting application is using it in resonators that vibrate at specific frequencies, depending on the sheet’s properties.

"These sheets are the thinnest structures that can be fabricated from nanoparticles," Jaeger says. "We build them particle by particle, so we can design them according to the needs of the researcher."

by Greg Borzo

This award is funded under the American Recovery and Reinvestment Act of 2009, NSF Award number:  0907075. For more information on NSF Recovery Act projects, visit

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