Comparison of dynamic and optical properties of Fe3O4 ferrofluid emulsion in water and oleic acid under magnetic field

The Fe3O4 ferrofluid emulsions in both distilled water and oleic acid were prepared by using Fe3O4 ferrofluid (SMG018), the sodium dodecyl sulfate (SDS), and distilled water or oleic acid. The optical transmission of these emulsions has been investigated as a function of incident optical wavelengths between 450 and 750 nm and applied magnetic fields up to 141 Oe. The transmittance increases as the applied magnetic fields increase. This phenomenon is more manifest with shorter incident wavelength. The transmittance for samples in oleic acid is much higher than that of samples in distilled water. Under the same perpendicular applied magnetic field, the area covered by the droplets of the emulsions for samples in oleic acid is smaller than that of samples in distilled water. These phenomena can be explained due to the different aggregation abilitation of the ferrofluid emulsions in both distilled water and oleic acid. (C) 2000 Elsevier Science B.V. All rights reserved.