Making Nanomaterials in Supercritical Fluids: A Review

Abstract

Using supercritical or near-supercritical fluids as media for physical or chemical transformations is an emerging technology for nanomaterials production. The unusual properties of supercritical fluids—including tunable solvent strength, high diffusivity, and low viscosity, as well as the ability to replace toxic solvents—offer materials processing in supercritical fluids significant advantages over conventional processes. Nanoparticles, nanowires, and thin solid films with high purity, uniformity, and homogeneity can be prepared in supercritical or near-supercritical fluids with minimum environmental problems. A number of nanomaterials processing techniques including rapid expansion of supercritical solutions (RESS), microemulsion reactions, supercritical fluid transport–chemical deposition (SFT–CD), supercritical fluid transport–chemical vapor deposition (SFT–CVD), supercritical fluid chemical deposition (SFCD), chemical fluid deposition (CFD), and supercritical fluid immersion deposition (SFID) are described.