Surface functionalized magnetic nanoparticles as switchable building blocks for soft nanotechnology

Abstract

α-Fe2O3 (hematite) particles can be synthesized by forced hydrolysis of iron salts. Playing with physical and chemical means allows the control of size and shape of the obtained ferromagnetic particles. Here we will summarize our recent work on the synthesis of hematite cubes and spindle type particles, which can be obtained with large aspect ratios such as 7. These particles can then be coated with a silica layer, allowing the creation of a specific surface functionality for their incorporation in polymer matrices or simply for their stabilization in a given solvent. We demonstrate that a moderate magnetic field (2-12mT) is sufficient to orient our particles, and how we can use them as nanoprobes to investigate local rheological properties of complex fluids.