The structure formation and dynamics of dilute, monodisperse ferrofluid emulsions under the influence of an external magnetic field have been investigated using static and dynamic light scattering techniques and optical microscopy. In the absence of the magnetic field induces a magnetic dipole moment in each particle. Dipolar interaction between particles align them into chains which may further coalesce to other larger structures. This microscopic structural transition changes viscosity dramatically and reversibly upon the removal of the field, leading to many potential applications such as vibration dampers. While the goal of the research is to understand the mechanism of the structure formation of magnetorheological fluids, this work focuses on the initial stage of the structure transition; static and dynamic properties of chain formation in a dilute system. The time dependence of the structure formation as a function of the field strength is studied by the static light scattering. The change of the dynamic properties of the fluid due to chain formation is studied by the dynamic light scattering.
Liu, J., Hagenbuchle, M., Sheaffer, P., Zhu, Y., Static and Dynamic Properties of Chain Formation in a Dilute Magnetorheological Fluid, 6th Int. Space Comf. Pacific Basin Societies, Marina del rey, CA, pp. 1-9, December 6, 1995.