Rex M, Löwen H
Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, Düsseldorf, Germany.
Eur Phys J E Soft Matter. 2008 May-Jun;26(1-2):143-50. doi: 10.1140/epje/i2007-10274-4. Epub 2008 Mar 6.
The influence of hydrodynamic interactions on lane formation of oppositely charged driven colloidal suspensions is investigated using Brownian dynamics computer simulations performed on the Rotne-Prager level of the mobility tensor. Two cases are considered, namely sedimentation and electrophoresis. In the latter case the Oseen contribution to the mobility tensor is screened due to the opposite motion of counterions. The simulation results are compared to that resulting from simple Brownian dynamics where hydrodynamic interactions are neglected. For sedimentation, we find that hydrodynamic interactions strongly disfavor laning. In the steady state of lanes, a macroscopic phase separation of lanes is observed. This is in marked contrast to the simple Brownian case where a finite size of lanes was obtained in the steady state. For strong Coulomb interactions between the colloidal particles a lateral square lattice of oppositely driven lanes is stable similar to the simple Brownian dynamics. In an electric field, on the other hand, the behavior is found in qualitative and quantitative accordance with the case of neglected hydrodynamics.
利用在迁移率张量的Rotne-Prager水平上进行的布朗动力学计算机模拟，研究了流体动力学相互作用对带相反电荷的驱动胶体悬浮液中条带形成的影响。考虑了两种情况，即沉降和电泳。在后一种情况下，由于反离子的反向运动，奥森对迁移率张量的贡献被屏蔽。将模拟结果与忽略流体动力学相互作用的简单布朗动力学结果进行了比较。对于沉降，我们发现流体动力学相互作用强烈不利于条带形成。在条带的稳态下，观察到条带的宏观相分离。这与简单布朗情况形成鲜明对比，在简单布朗情况下，稳态下获得了有限尺寸的条带。对于胶体颗粒之间强的库仑相互作用，与简单布朗动力学类似，反向驱动条带的横向方形晶格是稳定的。另一方面，在电场中，发现其行为在定性和定量上与忽略流体动力学的情况一致。
