Adsorption of colloidal particles by Brownian dynamics simulation: Kinetics and surface structures
Adsorption of colloidal particles by Brownian dynamics simulation: Kinetics and surface structures
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DOI：
10.1063/1.1319317
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发表时间：
2001-01-15
影响因子：
4.4
通讯作者：
Bonnecaze, RT
中科院分区：
文献类型：
--
作者：
Gray, JJ;Bonnecaze, RT
仔细控制吸附的胶体颗粒单分子层的微观结构对于通过自组装过程创建纳米结构设备非常重要。我们提出了胶体或纳米粒子系统自组装的计算模型研究。我们开发了一种新的技术来模拟胶体吸附过程，并研究了表面的动力学和结构形成。该技术允许模拟具有开放边界的非均匀悬浮体，该非均匀悬浮体与已知体积分数的块体悬浮体是平衡的，包括来自体溶液的平均场力和模拟盒和体积体之间的粒子通量。短时动力学遵循与扩散受限吸附相似的幂定律。长期动力学符合2/3次方定律形式[P.Schaaf，A.Johner，和J.Talbot，Phys.莱特牧师。66,1603(1991)]，并计算了动力学系数。颗粒的Zeta电位是控制最终表面覆盖率的主要参数，而吸附表面的Zeta电位是决定吸附体系有序性的主要因素。德拜层较大(盐浓度较低)的粒子更容易排序。将干扰极限覆盖与现有的等效硬盘模型和能量模型进行了比较。由于这一过程在动力学上受挫，粒子排斥效应在决定覆盖范围和结构方面发挥了重要作用。(C)2001年美国物理研究所。
Careful control of the microstructure of an adsorbed monolayer of colloidal particles is important for creating nanostructured devices through self-assembly processes. We present a computational model study for self-assembly of colloidal or nanoscale particulate systems. We develop a new technique for simulating colloidal adsorption processes, and we examine the kinetics and the structure formation on the surface. The technique allows the simulation of a nonhomogeneous suspension with an open boundary that is in equilibrium with a bulk suspension of known volume fraction, including the mean-field forces from the bulk solution and particle flux between the simulation box and the bulk. Short-time kinetics follow a power law similar to the case of diffusion-limited adsorption. Long-time kinetics fit a 2/3-power law form [P. Schaaf, A. Johner, and J. Talbot, Phys. Rev. Lett. 66, 1603 (1991)] and kinetic coefficients are calculated. The zeta potential of the particles is the dominant parameter controlling the final surface coverage, but the zeta potential of the adsorbing surface is the dominant control for the ordering of the adsorbed system. Particles with larger Debye layers (lower salt concentrations) order more easily. Jamming limit coverages are compared to existing equivalent hard-disk models and an energetic model. Since the process is kinetically frustrated, particle exclusion effects play a major role in determining coverage as well as structure. (C) 2001 American Institute of Physics.