Monodisperse titania microspheres via controlled nanoparticle aggregation

Abstract

This paper describes the fabrication of highly monodisperse TiO₂ nanoparticle aggregates (NPAs) by controlled aggregation of nanoparticles in a water-in-oil emulsion. Equally sized drops containing a titanium dioxide nanoparticle suspension are produced in a T-channel device. This procedure has a high tuning potential. Increasing the velocity of the titania suspension phase leads to an enlargement of the droplets, while raising the velocity of the oil phase reduces the drop diameter. The technique enables the preparation of monodisperse (<2%) drops between 150 and 400 μm in diameter. Evaporation of the suspension medium leads to nanoparticle aggregates. There is no significant change in dispersity from emulsion drops to NPAs, if the drying is carried out slowly.