Hütter M
ETH Zürich, Department of Materials, Institute of Polymers and Swiss Rheocenter, Zürich, CH-8092, Switzerland
J Colloid Interface Sci. 2000 Nov 15;231(2):337-350. doi: 10.1006/jcis.2000.7150.
The effect of solid content and colloidal interactions on the structure of forming networks of colloidal particles is studied by Brownian dynamics simulation. The different situations are compared in terms of the pair distribution function and the distribution of nearest neighbors around each particle. The results indicate that, in fast coagulation, the higher solid contents lead to a freezing-in of the liquid structure. Nevertheless, this effect can be reduced substantially by the introduction of a shallow secondary minimum and an energy barrier in the interaction potential. However, the structures resulting from such slow coagulation show a substantial degree of porosity, larger than those produced at the same solid content but by fast coagulation. It is also shown how the porosity (defined on a few particle diameters) is reflected in the distribution of nearest neighbors around the center particle, i.e., the very local conformation in the particle network. Fractal analysis shows that, at the relatively high volume fractions considered in this study, no intermediate fractal regime exists. Copyright 2000 Academic Press.
通过布朗动力学模拟研究了固体含量和胶体相互作用对胶体颗粒形成网络结构的影响。根据对分布函数和每个颗粒周围最近邻分布情况对不同情形进行了比较。结果表明，在快速凝聚过程中，较高的固体含量会导致液体结构的冻结。然而，通过在相互作用势中引入一个浅的二级极小值和一个能垒，这种效应可以大幅降低。不过，这种缓慢凝聚产生的结构显示出相当程度的孔隙率，比在相同固体含量下通过快速凝聚产生的结构的孔隙率更大。研究还表明了孔隙率（在几个颗粒直径范围内定义）如何反映在中心颗粒周围最近邻的分布中，即颗粒网络中的局部构象。分形分析表明，在本研究中考虑的相对较高的体积分数下，不存在中间分形区域。版权所有2000年学术出版社。
