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arXiv · 1706.06307

Diffusiophoretic manipulation of particles in a drop deposited on a hydrogel

François Boulogne·Sangwoo Shin·Julien Dervaux·Laurent Limat·Howard A. Stone
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Abstract

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.

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François Boulogne, Sangwoo Shin, Julien Dervaux, Laurent Limat, Howard A. Stone. 2017-06-20. Diffusiophoretic manipulation of particles in a drop deposited on a hydrogel. https://doi.org/10.1039/c7sm00915a

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