Nanoparticle separation and deposition processing using gas expanded liquid technology

Most currently employed nanoparticle post-synthesis processing techniques are solvent intensive and time consuming. This article reviews the development of highly tunable CO2 gas-expanded liquid (GXL) systems to process nanoparticles in a sustainable and efficient manner. The highly adjustable physico-chemical properties of these GXLs provide unique opportunities to control nanoparticle dispersability and precipitation through simple variations in applied CO2 pressure. This article illustrates that these tunable solvent systems can be used to create high quality, wide-area nanoparticle thin films and can also be used for the size-selective fractionation of ligand stabilized metallic nanoparticles. Recent advancements in the development of models that accurately predict nanoparticle dispersability in these tunable solvent systems are also described.

► Nanoparticle processing using the tunable properties of gas-expanded liquids.
► Gas-expanded liquids to controllably precipitate nanoparticles from a dispersion.
► Creation of extremely high quality, nanoparticle thin film monolayers.
► Efficient size-selective fractionation of nanoparticles without producing waste.
► Thermodynamic model to predict the size distribution of dispersed nanoparticles.