磁性扁平粒子からなるコロイド分散系の擬2次元モンテカルロ・シミュレーション(流体工学,流体機械)

Abstract

We have investigated aggregation phenomena of a colloidal dispersion composed of magnetic plate-like particles by means of Monte Carlo method. Such plate-like particles have been modeled as disk-like particles with a magnetic moment normal to the particle axis at the particle center, with the side section shape of a spherocylinder. The main objective of the present study is to clarify the influences of the magnetic field strength and magnetic interactions between particles on particle aggregation phenomena. We have concentrated our attention on a quasi-2D system from an application point of view such as development of surface changing technology using such magnetic plate-like particles. Internal structures of particle aggregates have been discussed quantitatively in terms of radial distribution and orientational pair correlation functions. The main results obtained here are summarised as follows. For the case of strong magnetic interactions between particles, particles form long cookie-like clusters and alternate between magnetic moments. This tendency appears under circumstances of a weak applied magnetic field. However, as the magnetic field strength becomes significant, particle inclines toward the magnetic field direction, so that the particles do not form the clusters.