Diffusiophoresis in narrow channel flows
Diffusiophoresis in narrow channel flows
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DOI：
10.1017/jfm.2018.618
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发表时间：
2018-09-10
影响因子：
3.7
通讯作者：
Stone, Howard A.
中科院分区：
文献类型：
--
作者：
Ault, Jesse T.;Shin, Sangwoo;Stone, Howard A.
含有悬浮胶体颗粒和溶解溶质的流存在于许多天然和人造系统中，包括水力压裂、水过滤系统和微流体装置，例如为生物或医学应用设计的那些。在这些类型的系统中，由于流体平流和颗粒扩散电泳的合作或竞争效应，在局部溶质梯度存在下观察到了意外的颗粒动力学，例如快速颗粒运输和聚焦，后者由局部化学梯度驱动。我们开发的流体，溶质和颗粒的动力学在长，窄的通道，由于压力驱动的通道流与扩散电泳和扩散渗透效应的综合影响的解析表达式。结果证实了一个快速的粒子聚焦效果，可以通过操纵粒子，溶质和流动特性，以及通道的几何形状和表面化学控制。因此，我们提出了一种新的方法进行微流控zeta电位，以及分选，浓缩和/或捕获基于其大小或zeta电位的颗粒的技术。最后，我们证明了扩散渗透效应可以用来泵送流体对压力梯度。
Flows containing suspended colloidal particles and dissolved solutes are found in a multitude of natural and man-made systems including hydraulic fractures, water filtration systems and microfluidic devices, e.g.those designed for biological or medical applications. In these types of systems, unexpected particle dynamics such as rapid particle transport and focusing has been observed in the presence of local solute gradients due to the cooperating or competing effects of fluid advection and particle diffusiophoresis, the latter driven by local chemical gradients. We develop analytical expressions for the fluid, solute and particle dynamics in long, narrow channels due to the combined influence of pressure-driven channel flow with diffusiophoretic and diffusioosmotic effects. The results confirm a rapid particle focusing effect that can be controlled by manipulating the particle, solute and flow properties, as well as the channel's geometry and surface chemistry. Thus, we propose a new approach for performing microfluidic zeta potentiometry, as well as techniques for sorting, concentrating and/or capturing particles based on their sizes or zeta potentials. Finally, we demonstrate that diffusioosmotic effects can be used to pump fluid against a pressure gradient.