Fluid rheological effects on streaming dielectrophoresis in a post‐array microchannel
Fluid rheological effects on streaming dielectrophoresis in a post‐array microchannel
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阵列后微通道中流体流变学对流式介电泳的影响
DOI：
10.1002/elps.202100270
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发表时间：
2021
期刊：
影响因子：
2.9
通讯作者：
Xuan, Xiangchun
中科院分区：
文献类型：
--
作者：
Bentor, Joseph;Raihan, Mahmud Kamal;McNeely, Colin;Liu, Zhijian;Song, Yongxin;Xuan, Xiangchun
最近的研究表明，在单收缩微通道中，流体流变特性对绝缘体基介电电泳（iDEP）有很强的影响。然而，非牛顿流体中的iDEP是如何取决于绝缘结构的几何形状的，这一点尚不清楚。在这项工作中，我们报告了流体流变学对后阵列微通道中呈现多重收缩和膨胀的流动DEP的影响的实验研究。粘弹性聚乙烯氧化物溶液中粒子的iDEP聚焦和捕获与牛顿缓冲液中粒子的iDEP聚焦和捕获相当，这与单收缩微通道中的观察结果一致。同样，在剪切变薄的黄原胶溶液中，不显著的iDEP效应也与单收缩通道中的iDEP效应一致，只是观察到凝胶样结构只在大直流电场下的后阵列微通道中形成。相比之下，粘弹性和剪切减薄聚丙烯酰胺溶液中的iDEP效应明显弱于单收缩通道。此外，不稳定性发生在电渗透流动中，似乎只依赖于直流电场。这些现象可能与聚合物的动力学有关，因为它们是电动地在柱子周围平流并通过柱子。
Recent studies have demonstrated the strong influences of fluid rheological properties on insulator‐based dielectrophoresis (iDEP) in single‐constriction microchannels. However, it is yet to be understood how iDEP in non‐Newtonian fluids depends on the geometry of insulating structures. We report in this work an experimental study of fluid rheological effects on streaming DEP in a post‐array microchannel that presents multiple contractions and expansions. The iDEP focusing and trapping of particles in a viscoelastic polyethylene oxide solution are comparable to those in a Newtonian buffer, which is consistent with the observations in a single‐constriction microchannel. Similarly, the insignificant iDEP effects in a shear‐thinning xanthan gum solution also agree with those in the single‐constriction channel except that gel‐like structures are observed to only form in the post‐array microchannel under large DC electric fields. In contrast, the iDEP effects in both viscoelastic and shear‐thinning polyacrylamide solution are significantly weaker than in the single‐constriction channel. Moreover, instabilities occur in the electroosmotic flow and appear to be only dependent on the DC electric field. These phenomena may be associated with the dynamics of polymers as they are electrokinetically advected around and through the posts.