Diffusion microrheology of ferrofluids

Abstract

We provide a statistical mechanics approach to study the linear microrheology of thermally equilibrated and homogeneous ferrofluids. Theexpressions for the elastic and loss moduli depend on the bulk microstructure of the magnetic fluid determined by the structure factor of thesuspension of magnetic particles. The comparison of the predicted microrheology with computer simulations confirms that as a function ofrelaxation frequency of thermal fluctuations of the particle concentration both theory and simulations have the same trends. At very shortfrequencies the viscous modulus relates to the translational and rotational self-diffusion coefficients of a ferro-particle.