Magnetophoretic Equilibrium of a Polydisperse Ferrofluid

The equilibrium concentration distribution of magnetic nanoparticles in a nonuniform magnetic field is studied theoretically. A linear current-carrying wire is used as a source of a nonuniform field. An exact solution for the concentration profile of a dilute monodisperse suspension is obtained within the framework of the continuous mass transfer theory. The applicability of this solution in a broad range of amperage values is tested using Langevin dynamics simulations. Obtained solution is also generalized for polydisperse suspensions. It is demonstrated that the particle size distribution in a polydisperse system strongly depends on the distance from the wire and in general does not coincide with the original distribution of a uniform suspension.

Automated summary

The study investigates the equilibrium concentration distribution of magnetic nanoparticles in a nonuniform magnetic field, obtaining an exact solution for dilute monodisperse suspensions and testing its applicability in a broad range of amperage values. The solution is also generalized for polydisperse suspensions, revealing that particle size distribution in such systems strongly depends on the distance from the wire and generally does not coincide with the original distribution of a uniform suspension.