Magnetoviscous effect in ferrofluids with different dispersion media

• Ferrofluids based on mixed surfactants were synthesized.
• Oleic, stearic acid and alkenylsuccinic anhydride were used.
• The nature of the surfactant has a high impact on the ferrofluids' shear viscosity.
• The core size distribution is not the only determining reason of the structuring.
• Significance of the interaction of the carrier medium and surfactant is demonstrated.

Ferrofluids based on magnetite nanoparticles dispersed in different carrier media (dialkyldiphenyl and polyethylsiloxane) have been synthesized using mixed surfactants (oleic acid, stearic acid and alkenyl succinic anhydride). Magnetic properties of the samples and a change of their shear viscosities in an applied magnetic field have been studied in order to evaluate an influence of the carrier medium on a magnetoviscous effect. A significance of the interaction of the carrier medium and surfactant with a consideration of the magnetic and rheological behavior of ferrofluids was demonstrated.