Non-uniform distribution of ferrofluids spherical particles under external electric field: Theoretical description

In the given work, we focus on the theoretical description of the electric field driven ferrofluids particles distribution. The obtained theoretical results show that the homogeneous distribution of dielectric particles in the dielectric carrier could become inhomogeneous under the applied electric field. The reason of the inhomogeneous development is polarization of the particles and their interaction as dipoles. Transition to an inhomogeneous distribution has a threshold character. The critical value of the applied field increases with increasing temperature, with a decrease in the number of particles and their radius. The critical value of the applied field also increases with decreasing difference between the dielectric permittivities of particles and medium. The found distribution of nanoparticle concentration according to the proposed theoretical approach is in good agreement with experimentally observed non-homogeneous distribution of the ferrofluids particles under external electric field. (C) 2019 Elsevier B.V. All rights reserved.