Aerogels are a fascinating class of high surface-area, mechanically-robust materials with a broad range of both commercial and fundamental scientific applications. Owing to its highly porous mass-fractal nanostructure, amorphous silica aerogel has been used as a capture agent in NASA's cometary-dust retrieval missions, to control disorder in 3He-superfluid phase transitions, in the fabrication of targets for laser inertial confinement fusion, in low-k microelectromechanical (MEMS) devices, and in Cherenkov nucleonic particle detectors.
In particular, amorphous carbon aerogel has received a considerable amount of attention in recent years owing to its low cost, electrical conductivity, mechanical strength, and thermal stability. Numerous applications have been explored for this material including water desalination, electrochemical supercapacitors, and thermal insulation.
Impressive advances have been made in the synthesis of polycrystalline aerogels through the oxidative aggregation of chalcogenide quantum dots that preserve spectral signatures of quantum confinement. Also, silicon divacancies in nanodiamond have also been shown to be bright single-photon-emitters at room temperature (Jelezko, Phys. Stat. Sol. A, 2006), as well as being photostable near-infrared biocompatible fluorophores (Lu, PNAS, 2007).
Furthermore, recent high-pressure, high temperature (HPHT) experiments with mesoporous silica have been employed to produce mesoporous coesite phase after oxidative removal of the carbon pressure medium. However, the achievement of an amorphous to crystalline phase transition in an aerogel material has remained an outstanding challenge, largely due to the difficulty in preventing pore collapse in the high surface area aerogel starting material.
In addition, thermal, electrical, optical, mechanical, and chemical properties of low-density amorphous aerogels can change profoundly through conversion from an amorphous to a crystalline phase, opening up new horizons for applications of this material in fundamental science.
Therefore, a method and system capable of synthesizing crystalline aerogel materials from amorphous aerogel precursors would have great utility in basic science and commercial applications.