Institut für Theoretische Physik, Hardenbergstrasse 36, Technische Universität Berlin, D-10623 Berlin, Germany.
Phys Rev E. 2017 Jun;95(6-1):062605. doi: 10.1103/PhysRevE.95.062605. Epub 2017 Jun 20.
Using Brownian dynamics simulations, we investigate a dense system of charged colloids exposed to shear flow in a confined (slit-pore) geometry. The equilibrium system at zero flow consists of three well-pronounced layers with a squarelike crystalline in-plane structure. We demonstrate that, for sufficiently large shear rates, the middle layer separates into two sublayers where the particles organize into moving lanes with opposite velocities. The formation of this "microlaned" state results in a destruction of the applied shear profile; it also has a strong impact on the structure of the system, and on its rheology as measured by the elements of the stress tensor. At higher shear rates, we observe a disordered state and finally a recrystallization reminiscent of the behavior of bilayer films. We also discuss the system size dependence and the robustness of the microlaned state against variations of the slit-pore width. In fact, for a pore width allowing for four layers, we observe a similar shear-induced state in which the system splits into two domains with opposite velocities.
使用布朗动力学模拟，我们研究了在受限（狭缝-孔）几何形状中暴露于剪切流的密集带电胶体系统。在零流速下的平衡系统由三个明显的层组成，具有方形的面内结晶结构。我们证明，对于足够大的剪切速率，中间层会分成两个亚层，其中粒子组织成具有相反速度的移动通道。这种“微通道化”状态的形成导致施加的剪切轮廓被破坏；它还对系统的结构及其流变学（由应力张量的元素测量）产生强烈影响。在更高的剪切速率下，我们观察到无序状态，最后是类似于双层膜行为的再结晶。我们还讨论了系统尺寸的依赖性和微通道化状态对狭缝孔宽度变化的稳健性。事实上，对于允许存在四层的孔宽度，我们观察到类似的剪切诱导状态，其中系统分裂成两个具有相反速度的域。
