Transmittance and dynamic properties of Fe3O4 ferrofluid emulsion in hexanes and oleic acid

摘要

The optical transmission of Fe3O4 ferrofluid emulsions in either hexanes (C6H14) or oleic acid (C18H34O2) has been investigated as a function of concentration of Fe3O4 ferrofluid between 6 and 100wt%, incident optical wavelengths between 450 and 750 ran and applied magnetic fields up to 325 Oe. The optical transmission increases with decreasing concentration of Fe3O4 ferrofluid emulsions from 50 to 6wt% for samples in either hexanes or oleic acid. However, under an applied magnetic field, the optical transmission decreases for samples in hexanes, and increases for samples in oleic acid. This can be explained as being due to a different aggregation ability of the magnetic colloidal particles. In hexanes, the aggregation of magnetic particles tends to increase the area covered by the magnetic colloidal particles. In oleic acid, however, the aggregation of magnetic colloidal particles tends to form pattern of mazes and thus to reduce the area covered by the magnetic colloidal particles. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 7]