Three-dimensional core-shell superstructures: mechanically strong aerogels.

Nanocasting conformal polymer coatings on preformed three-dimensional assemblies of nanoparticles, macroscopically classified as aerogels, reinforces the interparticle necks and increases the strength of the bulk material dramatically. For example, specific compressive strengths are reported to be higher than those for mild steel and aluminum, while the ability to store energy may surpass that of armor grade ceramics. Specific chemistries have been developed for cross-linking skeletal nanoparticles with polyureas and polyurethanes, epoxies, and polystyrene, while the technology has been demonstrated with ~30 different nanoparticle networks in addition to silica.