Effect of ionic strength on the initial dynamics of flocculation of polystyrene latex with polyelectrolyte
Effect of ionic strength on the initial dynamics of flocculation of polystyrene latex with polyelectrolyte
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DOI：
10.1006/jcis.1998.5564
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发表时间：
1998-08-15
影响因子：
9.9
通讯作者：
Adachi, Y
中科院分区：
文献类型：
--
作者：
Matsumoto, T;Adachi, Y
研究了离子强度对聚苯乙烯胶乳（PSL）粒子絮凝动力学的影响。絮凝实验是在标准化的混合流中进行的，该混合流是通过使用一个端对端旋转装置并通过改变离子强度和絮凝剂浓度而产生的。我们将注意力集中在絮凝的初始过程上，其特征在于絮凝速率显著高（第一阶段），随后絮凝速率突然降低（第二阶段）。絮凝率和电泳迁移率作为混合步骤的函数的组合测量揭示了PSL颗粒的裸露表面上吸附的过渡状态。在低离子强度条件下，吸附过程符合动力学控制，而在高离子强度条件下，动力学控制吸附的证据消失。然而，即使在后者中，在第一阶段的絮凝率是一个功能的絮凝剂浓度。这与非平衡絮凝的图像是一致的。相对于离子强度的交叉可以归因于随着离子强度的增加，聚电解质在胶体表面的柔性增加。(C)北京：科学出版社.
The effect of ionic strength on the kinetics of flocculation of polystyrene latex (PSL) particles induced by addition of excess polyelectrolyte was studied. The flocculation experiment was performed in the standardized mixing flow generated by using an end-over-end rotation apparatus and by changing the ionic strength and polyelectrolyte concentration. We focused our attention on the initial process of flocculation, which is characterized by a remarkably high rate of flocculation (the first stage) followed by an abrupt decrease in the flocculation rate (the second stage). The combined measurements of the rate of flocculation and the electrophoretic mobility as a function of mixing steps revealed a transient state of polyelectrolyte adsorbing on the bare surface of PSL particles. Under the conditions of low ionic strength, the picture is consistent with that of kinetically controlled adsorption of polyelectrolyte, while, under high ionic strength, the evidence of kinetically controlled adsorption disappeared. However, even in the latter, the rate of flocculation in the first stage was a function of polyelectrolyte concentration. This is consistent with a picture of nonequilibrium flocculation. A crossover with respect to ionic strength can be ascribed to an increase in flexibility of polyelectrolytes at colloidal surfaces with an increase in ionic strength. (C) 1998 Academic Press.