Supercritical Anti-Solvent Micronization: Control of Morphology and Particle Size
- Pp. 16-28 (13)Ernesto Reverchon and Iolanda De Marco
Supercritical antisolvent precipitation has been used to micronize several kinds of materials. Nanoparticles with mean diameters in the 30-200 nm range and microparticles in the 0.2-20 &#181;m range are the most frequently obtained morphologies. Sometimes, hollow expanded microparticles with diameters between about 10 and 200 &#181;m and crystals having various morphologies have been obtained. In this work, the relation between vapor liquid equilibria and the observed morphologies has been performed; possible formation mechanisms have been proposed. If the material is precipitated from a supercritical gaseous phase, expanded microparticles can be obtained; whereas, if the process is carried out at supercritical conditions, there is a competition between jet break-up and liquid surface tension vanishing characteristic times. If surface tension disappears before the jet break-up, nanoparticles are formed from a gas plume; otherwise, micrometric droplets generate spherical micrometric particles.