In situ microcalorimetric investigation on effects of surfactants on cluster-shaped Ni-doped Fe3O4 formation

Abstract

In situ calorimetric technology was firstly employed to study the effects of surfactants on the materials formation. In the present study, different kinds of surfactants were selected as additives during cluster-shaped Ni-doped Fe3O4 synthesis. Experimental results indicate that the surfactants reduced the particle size and changed the cationic distribution, compositions and magnetic properties of the as-synthesized materials. The microcalorimetric results demonstrate that the sample formation was endothermal and divided into five processes based on the heat-flow versus time curves. No significant effects of the surfactants on these processes were found. However, the surfactants addition affected the heat flow and the temperatures for peaks in these curves. The surfactant adsorption on the crystal facet and nuclei of the sample, and the interactions among surfactants and ions contained in the system may be mainly the reason for these effects. These results demonstrate different actions of surfactants and ligands on materials formation.