Light as a Feather, Stiffer Than a Board

Greer, assistant professor of materials science and mechanics, is part of a team of researchers from Caltech, HRL Laboratories, LLC, and the University of California, Irvine, who have developed the world’s lightest solid material, with a density of just 0.9 milligrams per cubic centimeter, or approximately 100 times lighter than Styrofoam™. Though the material is ultra-low in density, it has incredible strength and absorbs energy well, making it potentially useful for applications ranging from battery electrodes to protective shielding.

"We're entering a new era of materials science where material properties are determined not only by the microscopic makeup of the material but also by the architecture of the constituents," Greer says.

The new material, called a micro-lattice, relies, appropriately, on a lattice architecture: tiny hollow tubes made of nickel-phosphorous are angled to connect at nodes, forming repeating, asterisklike unit cells in three dimensions. Everything between the tubes is open air. In fact, the structure consists of 99.99% open volume.