Stoll S, Buffle J
Department of Inorganic, Analytical and Applied Chemistry, Sciences II, University of Geneva, 30 quai E. Ansermet, Geneva 4, CH - 1211, Switzerland
J Colloid Interface Sci. 1998 Sep 15;205(2):290-304. doi: 10.1006/jcis.1998.5644.
The flocculation of colloidal particles in the presence of adsorbing polymers is a key process in colloid science, as well as in the chemical and biological regulation of aquatic systems. Polymers can influence important physical properties of colloidal aggregates such as their densities and settling velocities, as well as their chemical properties, affecting the probability that two colloidal particles will stick together when they collide. The presence of polymers usually makes more difficult the application of a coagulation theory to colloidal suspensions and the interpretation of experimental observations. Knowledge of floc structures is a key factor in the understanding of flocculation processes, and simulation may provide useful insights required to interpret the results of experimental studies and elaborate new theoretical models. Although modeling leaves much room for more progress, researchers now find it indispensible from a fundamental point of view and for environmental applications. In this paper, we report a computer simulation study of a two- and three- dimensional model for bridging flocculation between large linear polymer chains and comparatively small colloidal particles. The floc structures are investigated as a function of chain/particle concentration ratio, chain conformation, and space dimension. The values of the sticking probabilities are chosen to emphasize colloid-chain interactions compared to colloid-colloid or chain-chain interactions. The results suggest that the floc morphology is strongly dependent on the chain conformation and to a slight extent on the chain/particle concentration ratio. In particular, colloid interactions with linear rods result in a network characterized by fractal dimensions significantly higher than those obtained on the basis of the Cluster-Cluster Aggregation models of colloids only, or by flocculation of colloids with coiled chains. Copyright 1998 Academic Press.
在吸附性聚合物存在的情况下，胶体颗粒的絮凝是胶体科学以及水系统化学和生物调节中的关键过程。聚合物可以影响胶体聚集体的重要物理性质，如它们的密度和沉降速度，以及它们的化学性质，影响两个胶体颗粒碰撞时粘在一起的概率。聚合物的存在通常使将凝聚理论应用于胶体悬浮液以及解释实验观察结果变得更加困难。絮凝结构的知识是理解絮凝过程的关键因素，模拟可以提供解释实验研究结果和阐述新理论模型所需的有用见解。尽管建模仍有很大的改进空间，但研究人员现在从基本观点和环境应用的角度发现它是不可或缺的。在本文中，我们报告了一个关于大型线性聚合物链与相对较小的胶体颗粒之间桥连絮凝的二维和三维模型的计算机模拟研究。研究了絮凝结构作为链/颗粒浓度比、链构象和空间维度的函数。选择粘附概率的值是为了强调与胶体-胶体或链-链相互作用相比的胶体-链相互作用。结果表明，絮凝形态强烈依赖于链构象，并且在一定程度上依赖于链/颗粒浓度比。特别是，与线性棒状胶体的相互作用导致一个网络，其分形维数显著高于仅基于胶体的簇-簇聚集模型或与卷曲链胶体絮凝所获得的分形维数。版权所有1998年学术出版社。
