Aerogel is a type of material structure created when the liquid in a gel-based substance is replaced with a gas, resulting in an ultralight solid with very low density and thermal conductivity. Invented by chemical engineer Samuel Stephens Kistler in the 1930s, aerogel is known by nicknames such as “frozen smoke” and “solid air,” given that it is composed of approximately 98 percent air. The first aerogel was silica based, and until 2011 it was the lightest human-made solid material until lighter carbon-based versions replaced it.
Aerographene is the most significant of these. The current world record holder as the lightest solid ever made, Aerographene has an ultralow density of 160 g/m3. For perspective, the density of air at room temperature is 1,200 g/m3, and the density of helium is 179 g/m3; thus, the new material is, remarkably, 7.5 times lighter than air and just lighter than helium—making it the second lightest known substance after hydrogen.
Discovered in 2013 by scientists at Zhejiang University, Aerographene is made using a new method called lyophilization, which involves freeze-drying hybrid solutions of carbon nanotubes and graphene, resulting in a carbon sponge. Because this sponge matches the size and shape of its container, Aerographene can be created in sizes up to thousands of cubic centimeters and in a variety of forms.
Initial applications include the cleanup of oil spills, since the material can rapidly absorb up to nine hundred times its weight in petroleum, as well as the manufacture of ultralight composites, insulation, and phase change materials for energy storage.
Contact: Zhejiang University, Hangzhou, China.
For more information, see Transmaterial Next: A Catalog of Materials that Redefine Our Future