A New High Rate Process for Nanoparticle Separation

There is no technology currently available for sorting nanoparticles by particle size. Furthermore, there is no commercially viable process for removing relatively large primary particles and aggregates from a nanopowder mass. High rate nanoparticle production processes invariably produce powders that have either a wide particle size distribution, or are aggregated. This is evidenced in the characteristics of commercially available nanopowders. In either case, a nanoparticle separation tool, which removes large primary particles and aggregates from a powder mass leading to a narrow size distribution, will be highly beneficial to drastically improve the nanopowder properties. Our proposed nanoparticle separation equipment can be used either in-line with production systems, or used off-line, i.e. independent of the nanopowder synthesis reactor. The basis for nanoparticle separation was demonstrated in Phase I by using a combination of aerodynamic focusing, external electrical field application and thermophoretic effects. The larger primary particles and larger aggregates were removed from a gas phase stream of nanoparticles by driving larger particles in one direction and the smaller particles in the other. The primary objectives of the Phase II program are to develop and optimize a prototype nanoparticle separation system and develop scaling factors for a pilot scale unit. Kilogram quantities of samples will be processed during the course of the Phase II program and provided to the Army and our commercialization partners for testing. In addition, the design of a pilot scale unit that can be operated either in-line with a nanopowder production system, or off-line, will be delivered to the Army. Several large corporations have agreed to work with us during the Phase II program and beyond to evaluate, develop, and market the proposed nanoparticle separation equipment.