Highly efficient and flexible preparation of water-dispersed Fe3O4 nanoclusters using a micromixer

Solvent exchange is widely used to synthesize magnetic nanoclusters (MNCs). However, it remains a challenge to increase the production and decrease the addition of surfactants, both of which are important for the application and functionalization of MNCs. Herein, we use a rapid and tunable mixing method to control the assembly of Fe 3 O 4 nanoparticles. This method involves shear-mixing in a channel of a T-junction micromixer. Smaller and more monodisperse MNCs were synthesized with less surfactant, when compared with conventional bulk synthesis. Varying the mixing rate and the formula of the magnetic suspension allowed for the flexible adjustment of the nanocluster size while maintaining a uniformly sized MNCs. The flow synthesis and ease of scale-up make this method potentially suitable for broad industrial application.