Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Université Paris Diderot, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, Paris, France.
Soft Matter. 2017 Aug 2;13(30):5122-5129. doi: 10.1039/c7sm00915a.
We report an experimental study on the manipulation of colloidal particles in a drop sitting on a hydrogel. The manipulation is achieved by diffusiophoresis, which describes a directed motion of particles induced by solute gradients. By letting the solute concentrations for the drop and the hydrogel be different, we control the motion of particles in a stable suspension, which is otherwise difficult to achieve. We show that diffusiophoresis can cause the particles to move either toward or away from the liquid-air interface depending on the direction of the solute gradient and the surface charge of the particles. We measure the particle adsorption experimentally and rationalize the results with a one-dimensional numerical model. We show that diffusiophoretic motion is significant at the lengthscale of a drop deposited on a hydrogel, which suggests a simple method for the deposition of particles on hydrogels.
我们报告了一项关于在水凝胶上的液滴中操纵胶体粒子的实验研究。这种操纵是通过扩散泳来实现的，它描述了由溶质梯度引起的粒子的定向运动。通过使液滴和水凝胶的溶质浓度不同，我们可以控制稳定悬浮液中的粒子运动，否则这很难实现。我们表明，扩散泳可以根据溶质梯度的方向和粒子的表面电荷，使粒子朝着或远离气-液界面移动。我们通过实验测量了粒子的吸附，并通过一维数值模型对结果进行了合理化。我们表明，扩散泳在液滴沉积在水凝胶上的长度尺度上是显著的，这为在水凝胶上沉积粒子提供了一种简单的方法。
