Computational Chemistry on Internal Structures and Rheological Properties of Functional Colloids in Non-equilibrium Fields

(1)讨论了非稀胶体分散体的基于团簇的Stokesian动力学方法。基于聚类的方法可以大大减少计算时间，因此，对于铁磁胶体分散体，它明显优于普通的SD方法。(2)研究了耗散粒子动力学方法的有效性，这是一种介观模拟技术。我们从耗散粒子的运动方程推导出了输运系数如粘度的表达式。从非平衡动力学模拟中可以清楚地看出，耗散力引起的粘度的理论值与非平衡动力学方法得到的模拟结果非常一致，除了在小密度范围内，因此，本方法是一种考虑胶体颗粒之间流体动力学相互作用的有希望的技术。(3)对磁性粒子和耗散粒子组成的色散，进一步研究了耗散粒子动力学方法的有效性。我们讨论了这两种不同粒子之间相互作用的各种模型，并得出结论，结果并不明显依赖于相互作用模型。(4)从理论上研究了在外加磁场作用下由铁磁球柱颗粒组成的致密胶体分散体的颗粒取向分布和粘度。应用平均场近似来考虑目标粒子与邻近簇中粒子之间的磁相互作用。用伽辽金法和逐次逼近法求解了取向分布函数的积分微分方程的基本方程，阐明了即使粒子间的磁相互作用为热能量级时，粒子间相互作用对粘度的影响也随着粒子体积分数的增加而显著增加。少

(1) We have discussed the cluster-based Stokesian dynamics method for non-dilute colloidal dispersions. The cluster-based method can drastically reduce the computation time, and, therefore, it is significantly superior to the ordinary SD method for ferromagnetic colloidal dispersions.(2) We have investigated the validity of the dissipative particle dynamics method, which is a mesoscopic simulation technique. We have derived expressions for transport coefficients such as viscosity, from the equation of motion of the dissipative particles. It is clarified from non-equilibrium dynamics simulations that the theoretical values of the viscosity due to dissipative forces are in good agreement with the simulation results obtained by the non equilibrium dynamics method, except in the range of small number densities and, therefore, that the present method is a hopeful technique for taking into account hydrodynamic interactions among colloidal particles.(3) We have also investigated the validity … More of the dissipative particle dynamics method for a dispersion composed of magnetic and dissipative particles. Various models as an interaction between these two different particles have been discussed and we have a conclusion that results are not significantly dependent on the interaction model.(4) We have theoretically investigated the particle orientational distribution and viscosity of a dense colloidal dispersion composed of ferromagnetic spherocylinder particles under circumstances of an applied magnetic field. The mean field approximation has been applied to take into account the magnetic interactions of the particle of interest with the other ones which belong to the neighboring clusters, besides its own cluster. It is clarified from solving the basic equation of the orientational distribution function, which is an integro-differential equation, by Galerkin's method and the method of successive approximation that, even when the magnetic interaction between particles is of the order of the thermal energy, the effect of particle-particle interactions on the viscosity comes to increase more significantly with increasing the volumetric fraction of particles. Less