Accumulation of Colloidal Particles in Flow Junctions Induced by Fluid Flow and Diffusiophoresis
Accumulation of Colloidal Particles in Flow Junctions Induced by Fluid Flow and Diffusiophoresis
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DOI：
10.1103/physrevx.7.041038
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发表时间：
2017-11-16
影响因子：
12.5
通讯作者：
Stone, Howard A.
中科院分区：
文献类型：
--
作者：
Shin, Sangwoo;Ault, Jesse T.;Stone, Howard A.
多孔介质中含有溶质和胶体颗粒的溶液的流动广泛存在于地下含水层、水力裂缝、河口或沿海栖息地、水过滤系统等系统中。在这样的系统中，当溶质浓度发生局部变化时，会发生溶质梯度。虽然溶质梯度的影响已被发现是重要的许多应用，我们观察到一个意想不到的胶体行为在多孔介质中的溶质梯度和流体流动的组合驱动。当具有不同溶质浓度的两个流在接头附近接触时，在界面处形成急剧的溶质梯度，这可以允许针对流的颗粒的强扩散电泳。因此，颗粒在孔入口附近积聚，迅速接近填充极限。这些胶体动力学对多孔介质的堵塞具有重要意义，其中比孔宽度小几个数量级的颗粒可以在短时间内积聚并堵塞孔。我们还表明，这种效果可以利用作为一个有用的工具，用于预浓缩生物分子的快速生物测定。
The flow of solutions containing solutes and colloidal particles in porous media is widely found in systems including underground aquifers, hydraulic fractures, estuarine or coastal habitats, water filtration systems, etc. In such systems, solute gradients occur when there is a local change in the solute concentration. While the effects of solute gradients have been found to be important for many applications, we observe an unexpected colloidal behavior in porous media driven by the combination of solute gradients and the fluid flow. When two flows with different solute concentrations are in contact near a junction, a sharp solute gradient is formed at the interface, which may allow strong diffusiophoresis of the particles directed against the flow. Consequently, the particles accumulate near the pore entrance, rapidly approaching the packing limit. These colloidal dynamics have important implications for the clogging of a porous medium, where particles that are orders of magnitude smaller than the pore width can accumulate and block the pores within a short period of time. We also show that this effect can be exploited as a useful tool for preconcentrating biomolecules for rapid bioassays.