Mini-review on application of analytical centrifugation, ultracentrifugation and centrifugal devices to phase equilibria and separation processes

Analytical centrifugation (AC) and analytical ultracentrifugation (AUC) are techniques that allow determination of nanoparticle and colloidal system properties relevant to fluid phase equilibria. AC/AUC techniques allow determination of nanoparticle density, molecular weight, size distribution, diffusion coefficients, coating or capping thickness, association and dispersion, species aggregation, geometric factors, and frictional coefficients. In this mini-review, AC/AUC studies are highlighted as they have been applied to determine the osmotic pressure equation of state for ferrofluids, colloidal systems (clays, polystyrene, photonic material self-assembly), determination of solid-liquid equilibria of mass transfer limited (high viscosity) chemical systems such as deep eutectic solvents, ionic liquids and process intensification devices such as centrifugal contactor separators. AC/AUC techniques can be applied to many types of biological and chemical systems and will greatly broaden the scope of research into fluid phase equilibria.