Soluto-inertial phenomena: Designing long-range, long-lasting, surface-specific interactions in suspensions
Soluto-inertial phenomena: Designing long-range, long-lasting, surface-specific interactions in suspensions
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DOI：
10.1073/pnas.1604743113
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发表时间：
2016-08-02
影响因子：
11.1
通讯作者：
Squires, Todd M.
中科院分区：
文献类型：
--
作者：
Banerjee, Anirudha;Williams, Ian;Squires, Todd M.
水悬浮液中颗粒之间的平衡相互作用被限制在小于1 μ m的距离内。在这里，我们描述了一个通用的概念来设计和工程非平衡相互作用，其大小和方向取决于悬浮颗粒的表面化学性质，其范围可以扩展到数百微米，持续数千秒。这里描述的机制依赖于扩散电泳，其中悬浮颗粒根据溶液中的梯度迁移。它涉及三个要素：一个解-惯性“信标”，设计用于在长时间尺度上发射稳定的溶质通量；随溶质通量而迁移的悬浮粒子；以及溶质本身，它调解了相互作用。我们展示了解-惯性相互作用，延伸近半毫米，持续数十分钟，根据悬浮粒子的表面化学性质，它们是吸引的还是排斥的。实验在定量上与尺度论点和数值计算一致，证实了基本现象，揭示了设计策略，并为操纵和控制悬浮粒子提供了广泛的新可能性。
Equilibrium interactions between particles in aqueous suspensions are limited to distances less than 1 mu m. Here, we describe a versatile concept to design and engineer nonequilibrium interactions whose magnitude and direction depends on the surface chemistry of the suspended particles, and whose range may extend over hundreds of microns and last thousands of seconds. The mechanism described here relies on diffusiophoresis, in which suspended particles migrate in response to gradients in solution. Three ingredients are involved: a soluto-inertial "beacon" designed to emit a steady flux of solute over long time scales; suspended particles that migrate in response to the solute flux; and the solute itself, which mediates the interaction. We demonstrate soluto-inertial interactions that extend for nearly half a millimeter and last for tens of minutes, and which are attractive or repulsive, depending on the surface chemistry of the suspended particles. Experiments agree quantitatively with scaling arguments and numerical computations, confirming the basic phenomenon, revealing design strategies, and suggesting a broad set of new possibilities for the manipulation and control of suspended particles.