Electro-elastic migration of particles in viscoelastic fluid flows
Electro-elastic migration of particles in viscoelastic fluid flows
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DOI：
10.1063/5.0167571
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发表时间：
2023-09
影响因子：
4.6
通讯作者：
Di Li;X. Xuan
中科院分区：
文献类型：
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作者：
Di Li;X. Xuan
颗粒的微流体操纵通常依赖于它们的交叉流迁移。已经报道了通过正或负电泳引导或滞后粘弹性聚环氧乙烷（PEO）溶液的Poiffille流的颗粒的中心或壁定向运动。这种电弹性迁移与牛顿流体流中粒子的电惯性迁移完全相反。我们在这里证明，通过顶视图和侧视图成像的PEO溶液的电流体动力学流动中的领先和落后的颗粒迁移到一个矩形微通道的中心线和角落，分别。这些电弹性颗粒迁移中的每一个都在具有较短聚合物的PEO溶液中减少，尽管它们都没有表现出对颗粒尺寸的强烈依赖性。这两种现象都可以用该理论根据参与该过程的力的比率来合理地解释。降低PEO的浓度会导致粒子迁移从粘弹性模式转移到牛顿模式，其中施加的电场的大小被发现起着重要的作用。
Microfluidic manipulation of particles usually relies on their cross-stream migration. A center- or wall-directed motion has been reported for particles leading or lagging the Poiseuille flow of viscoelastic polyethylene oxide (PEO) solution via positive or negative electrophoresis. Such electro-elastic migration is exactly opposite to the electro-inertial migration of particles in a Newtonian fluid flow. We demonstrate here through the top- and side-view imaging that the leading and lagging particles in the electro-hydrodynamic flow of PEO solution migrate toward the centerline and corners of a rectangular microchannel, respectively. Each of these electro-elastic particle migrations is reduced in the PEO solution with shorter polymers though neither of them exhibits a strong dependence on the particle size. Both phenomena can be reasonably explained by the theory in terms of the ratios of the forces involved in the process. Decreasing the PEO concentration causes the particle migration to shift from the viscoelastic mode to the Newtonian mode, for which the magnitude of the imposed electric field is found to play an important role.