Magnetite nanocrystal clusters transformed from ferric precursor and their colloidal magnetorheology

摘要

Spherical magnetite (Fe3O4) nanocrystal clusters (MNCs) were synthesized via reductive aging of ferric precursor (FeCl3-6H2O) in ethylene glycol (EG) in the presence of potassium acetate (KOAc). EG was used both as a reducing agent and a solvent. The as-synthesized MNCs with an average diameter of ~500nm comprised Fe3O4 nanocrystals with almost equal crystallographic orientation. The time-resolved evolution of the iron species was tracked, and the MNC transformation pathway from the ferric precursor in the solution was deduced. Moreover, to examine the feasibility of MNCs for a field-responsive material, magnetorheology was investigated for the MNC-dispersed colloid.