EFFECT OF POLYDISPERSITY ON MAGNETOVISCOUS PROPERTIES OF FERROFLUIDS.

The paper deals with a theoretical study of the magnetoviscous effect in polydisperse ferrofluids. A two-fractional model of colloid consisting of relatively large and small particles is studied. The model is based on the idea that the magnetoviscous effect is determined by chain-like aggregates formed by large particles. The effect of the small particle fraction is determined by two factors: (i) the magnetic interaction between large and small particles, which leads to a reduction of the chain length and weakening of the fluid magnetoviscosity, (ii) the steric interaction between small and large particles, which enlarges the chain length, therefore, enhances this effect. The resulting effect is determined by the ratio of the sizes of large and small particles. [ABSTRACT FROM AUTHOR]