Pangburn Todd O, Bevan Michael A
Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, USA.
J Chem Phys. 2006 Feb 7;124(5):054712. doi: 10.1063/1.2162536.
This paper investigates effects of using monodisperse inverse analyses to extract particle-particle and particle-surface potentials from simulated interfacial colloidal fluids of polydisperse attractive particles. Effects of polydispersity are investigated as functions of particle concentration and attractive well depth and range for van der Waals and depletion potentials. Forward Monte Carlo simulations are used to generate particle distribution functions for polydisperse interfacial colloidal fluids from which inverted potentials are obtained using an inverse Ornstein-Zernike analysis and an inverse Monte Carlo simulation method. Attractive potentials are successfully recovered for monodisperse colloidal fluids, but polydispersity that is unaccounted for in inverse analyses produces (1) apparent softening of strong forces, (2) anomalous repulsive and attractive interactions, and (3) aphysical particle overlaps. This investigation provides insights into the role of polydispersity in altering the equilibrium structure and corresponding inverted potentials of attractive colloidal fluids near surfaces. These findings should assist the design and interpretation of optical microscopy experiments involving interfacial colloidal fluids similar to the simulated experiments reported here.
本文研究了使用单分散逆分析从多分散吸引性颗粒的模拟界面胶体流体中提取颗粒-颗粒和颗粒-表面势的效果。研究了多分散性作为颗粒浓度以及范德华势和耗尽势的吸引阱深度与范围的函数的影响。正向蒙特卡罗模拟用于生成多分散界面胶体流体的颗粒分布函数，通过逆奥恩斯坦-泽尼克分析和逆蒙特卡罗模拟方法从中获得反转势。对于单分散胶体流体，吸引势成功恢复，但逆分析中未考虑的多分散性会产生：（1）强力的明显软化；（2）异常的排斥和吸引相互作用；（3）非物理的颗粒重叠。本研究深入了解了多分散性在改变表面附近吸引性胶体流体的平衡结构和相应反转势方面的作用。这些发现应有助于设计和解释与本文报道的模拟实验类似的涉及界面胶体流体的光学显微镜实验。
