Though we are the smartest animals on the planet, we still have things to learn from Nature. For example, the skeletons of some organisms are stronger than similar manmade materials. Researchers at the California Institute of Technology though have found a way to mimic these materials' strength with structures that are over 85% air.
The key to the skeletons and Caltech's materials are how they are built up of micro and nanoscale cells. At this size, the materials' strength and density need no longer be linked, which allows them to be very light yet still strong. Using two-photon lithography the researchers created a polymer lattice that mimic's the lattice of diatoms, a type of algae. A thin layer of the ceramic, titanium nitride was then deposited on the lattice, before the polymer core was removed. This left a hollow, ceramic structure, with walls no thicker than 75 nm, which withstood greater stress than a solid block of the ceramic.
While the strength of this lattice structure is definitely valuable, the true potential from this research may come from other it being applied to other materials. In theory any material, including metals and semiconductors, that can be deposited onto the polymer lattice could be used to create these structures, and bring with them new, interesting properties.