2. Nanoparticle synthesis for ferrofluid production

2.1 Stability criteria for ferrofluids

To use ferrofluid as such, it must be stable even under the action of a magnetic field.

In order to make the colloidal suspension homogeneous and stable, the particles must be small enough for thermal agitation to compensate for gravity, and short-range repulsive interactions must be established between the nanoparticles to prevent agglomeration and/or complete separation from the solvent. Suspending magnetic nanoparticles and controlling suspension stability is a major challenge. The following paragraph explains the various parameters to be taken into account when preparing a ferrofluid that is stable over time.

The stabilization of dilute dispersions of charged particles can be described by the...