Particle Size-Dependent Electrophoresis in Polymer Solutions
Particle Size-Dependent Electrophoresis in Polymer Solutions
复制标题
聚合物溶液中的粒径依赖性电泳
DOI：
10.1021/acs.analchem.3c05655
复制
发表时间：
2024
影响因子：
7.4
通讯作者：
Xuan, Xiangchun
中科院分区：
文献类型：
--
作者：
Bentor, Joseph;Xuan, Xiangchun
在薄德拜层极限下，带电粒子的电泳速度与其大小无关，这一点早已为人们所知。然而，这种所谓的Smoluchowski速度仅对牛顿流体有效。最近的一对夫妇的理论研究预测的流变诱导的非牛顿流体中的电泳的粒径依赖性。这项工作提出了第一个实验证明这种依赖性的粘弹性聚（环氧乙烷）（PEO）的解决方案。三个不同尺寸的粒子被观察到在牛顿缓冲液中以相同的电泳速度通过矩形微通道。相反，他们在PEO溶液中测得的电泳速度表现出增加的趋势，为较大的颗粒，这是与理论预测一致。发现这种粒度依赖性随着PEO聚合物的浓度或长度的增加而增长。这两种趋势都归因于流体弹性的增强，其特征在于弹性数的增加。
It has long been known that the electrophoretic velocity of a charged particle is independent of its size under the thin-Debye-layer limit. This so-called Smoluchowski velocity is, however, valid only for Newtonian fluids. A couple of recent theoretical studies predict the rheology-induced particle size dependence of electrophoresis in non-Newtonian fluids. This work presents the first experimental demonstration of such dependence in viscoelastic poly(ethylene oxide) (PEO) solutions. Three different-sized particles are observed to travel at the same electrophoretic velocity in a Newtonian buffer through a rectangular microchannel. In contrast, their measured electrophoretic velocities in the PEO solution exhibit an increasing trend for larger particles, which is consistent with theoretical prediction. This particle size dependence is found to grow with an increasing concentration or length of the PEO polymer. Both trends are attributed to enhanced fluid elasticity, as characterized by the increasing elasticity number.