Rheology and orientational distributions of rodlike particles with magnetic moment normal to the particle axis for semi-dense dispersions (analysis by means of mean field approximation)

On the orientational characteristics and transport coefficients of an oblate spheroidal hematite particle in a simple shear flow

“…That is, systematic studies have been carried out for a dilute dispersion [32], a semi-dilute dispersion [33] in which the interactions with the other particles belonging to the same cluster are taken into account, and for a dense dispersion [34] in which the interactions with the particles belonging to other neighboring clusters are considered. Moreover, these kinds of investigations have been expanded to a suspension composed of rodlike hematite particles [35][36][37]. From these theoretical studies, a negative magneto-rheological effect, in which the contribution to viscosity due to the magnetic properties becomes negative, has been found to arise [36,37].…”

“…Moreover, these kinds of investigations have been expanded to a suspension composed of rodlike hematite particles [35][36][37]. From these theoretical studies, a negative magneto-rheological effect, in which the contribution to viscosity due to the magnetic properties becomes negative, has been found to arise [36,37].…”

Influences of magnetic particle–particle interactions on orientational distributions and rheological properties for a colloidal dispersion composed of rod-like particle with a magnetic moment normal to the particle axis

“…In the present cluster model, the rod-like particles aggregate in the mean direction with a separation l between each pair of neighboring particles, and every rod-like particle has the same orientational distribution of the central particle of interest. As in the previous study [19], by summing the magnetic field made by the upper and lower areas in Fig. 2, the magnetic field induced at the center of the central particle can be obtained as:…”

Brownian dynamics simulation of a dispersion composed of disk-like hematite particles regarding the orientational distribution and the magneto-rheological properties

“…In contrast, hematite particles exhibit quite different characteristics because they are magnetized in a direction normal to the particle axis direction, and exhibit much weaker magnetization than magnetite [32][33][34][35]. In hematite particles the magnetization direction gives rise to two degrees of freedom regarding the rotational motion, that is, the usual rotational motion about a line normal to the particle axis and the spin rotational motion about the particle axis direction [36][37][38][39]. Currently, by expanding the ordinary synthesis technology, the challenge of developing new magnetorheological fluids has created an interest in new hematite particles with a variety of shape such as rod-like, oblate spheroidal and cubic-like [40,41].…”