pH effects on shear thickening behaviors of polystyrene-ethylacrylate colloidal dispersions
pH effects on shear thickening behaviors of polystyrene-ethylacrylate colloidal dispersions
复制标题
pH值对聚苯乙烯-丙烯酸乙酯胶体分散体剪切增稠行为的影响
DOI：
10.1088/2053-1591/1/1/015303
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发表时间：
2014-03-01
影响因子：
2.3
通讯作者：
Xuan, Shouhu
中科院分区：
文献类型：
--
作者：
Chen, Qian;Zhu, Wei;Xuan, Shouhu
在这项研究中，pH值的剪切增稠行为的影响进行了研究的基础上组成的聚苯乙烯-丙烯酸乙酯（PSt-EA）共聚物纳米球的浓缩分散体。通过添加不同种类的酸、碱溶液控制剪切增稠液的pH值，流变学测试表明PSt-EA胶体分散体的剪切增稠行为与体系的pH值有显著的依赖关系，体系的Zeta电位在pH = 3或9时趋于零。由于共聚物纳米球的表面性质发生了变化，在酸性条件下其等电点为3，而加入碱后其等电点变为9。降低和提高等电点附近的pH值都能降低悬浮液的临界剪切速率，有利于ST行为的发生。pH值的影响可以定性地解释通过使用聚类机制，其属性的现象，形成临时的，流体动力学集群。
In this study, the effects of pH on shear thickening behaviors were investigated based on concentrated dispersions consisting of polystyrene-ethylacrylate (PSt-EA) copolymer nanospheres. The pH values of the above shear thickening fluids were controlled by adding different kinds of acid and alkali solutions, and the rheological testing indicated that the shear thickening behaviors of PSt-EA colloidal dispersions is significantly dependent on the system’s pH. Zeta potential of this system tends to be close to zero at a pH of 3 or 9. Since the surface characteristics of copolymer nanospheres were changed, the isoelectric point is 3 in the acid circumstance, while the isoelectric point turns to be 9 by adding alkali. Both decreasing and increasing the pH value near to the isoelectric point can lower the critical shear rate of suspensions and make it easier for the ST behavior to take place. The effect of pH can be qualitatively explained by using a clustering mechanism, which attributes the phenomena to the formation of temporary, hydrodynamic clusters.