Computer Simulations of Structure, Dynamics, and Phase Behavior of Colloidal Fluids in Confined Geometry and under Shear (A05)

受限几何和剪切下胶体流体的结构、动力学和相行为的计算机模拟 (A05)

• 批准号: 5392695
• 金额: --
• 依托单位: Institut für Physik
• 依托单位国家: 德国
• 项目类别: CRC/Transregios
• 财政年份: 2002
• 资助国家: 德国
• 起止时间: 2001-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5392695?language=en
• 关键词: Computer; Simulations; Structure; Dynamics; Phase

Two types of colloidal systems exposed to shear deformation will be studied, a modelfor colloid-polymer mixtures under confinement, and a glass-forming binary soft spheremixture. Polymers are described as soft spheres weakly interacting with each other,while colloid-polymer and colloid-colloid pairs interact with the (repulsive) Weeks-Chandler-Andersen potential, so that a depletion attraction between colloids results,similar to the Asakura-Oosawa model. Confining this system between parallel plates,the interplay between phase separation and shear will be studied by Non-EquilibriumMolecular Dynamics, including the suppression of capillary waves at confined interfacesby the shear. Confinement in cylindrical geometry will also be considered. Theglass forming mixture is described by particles interacting with Yukawa potentials, andshear is implemented via Lees-Edwards boundary conditions. The study of transienttime-dependent phenomena will be extended to systems under oscillatory shear and tosystems that are subject to a constant shear stress. The latter problem is the macrorheologicalcounterpart to the micro-rheological simulation of a pulled probe particle,thus enabling to elucidate the relation between micro- and macro-rheology. The resultsof the simulation will be compared to those from mode-coupling theory and experiment.

将研究两种类型的受到剪切变形的胶体系统：约束下的胶体-聚合物混合物模型和玻璃形成二元软球混合物。聚合物被描述为彼此弱相互作用的软球体，而胶体-聚合物和胶体-胶体对与（排斥的）Weeks-Chandler-Andersen势相互作用，从而导致胶体之间产生耗尽吸引力，类似于Asakura-Oosawa模型。将该系统限制在平行板之间，通过非平衡分子动力学研究相分离和剪切之间的相互作用，包括剪切对受限界面处毛细波的抑制。还将考虑圆柱形几何形状的限制。形成玻璃的混合物由颗粒与汤川势相互作用来描述，剪切力是通过 Lees-Edwards 边界条件实现的。对瞬态时间相关现象的研究将扩展到振荡剪切下的系统和受到恒定剪切应力的系统。后一个问题是与拉动探针颗粒的微观流变模拟相对应的宏观流变问题，从而能够阐明微观流变学和宏观流变学之间的关系。模拟结果将与模式耦合理论和实验的结果进行比较。