Effect of friction between particles in the dynamic response of model magnetic structures

A simple particle-level simulation model that takes into account interparticle friction forces is developed to describe the dynamic response of magneto-rheological fluids. The results obtained for single-width particle chains are found to be in good agreement with slender body theory predictions [J. de Vicente, M.T. López-López, J.D.G. Durán, G. Bossis, J. Colloid Interface Sci. 282 (2005) 193]. The addition of side chains to a single-width one results in one order of magnitude increase of storage modulus and relaxation. The double logarithmic plot of storage and loss moduli vs frequency gives a limiting slope of one when including friction forces between particles. Simulation results are found to be in agreement with experimental measurements on an iron/kerosene model MR-fluid.