(402g) Clogging of Microchannels by Colloidal Particles: From Hydrodynamics to Surface Chemistry

Filtration technologies such as membranes rely on the retention of colloidal particles in porous structures. The accumulation of particles contributes to the fouling of the membrane and eventually leads to the clogging of the pores. In order to better understand the clogging process, model porous systems have recently been introduced \footnote{H. M. Wyss, D. L. Blair, J. F. Morris, H. A. Stone, D. A. Weitz, Phys. Rev. E \textbf{74}, 061402 (2006)}. It was shown that the number of particles that pass through a microfluidic channel before it is clogged depends on the ratio of pore to particle size, and is independent of the flow rate and the particle volume fraction.

Here, we report on the clogging of microfabricated channels by solid and soft colloidal particles. We demonstrate that the clogging probability can be strongly modified by a wide array of physicochemical parameters. By varying the features of the colloidal particles (size, density, surface properties, and softness) and the characteristics of the liquid phase (viscosity, ionic strength, and fluid velocity), we show that clogging strongly depends on (i) the ratio of the particle size to channel radius, (ii) the interactions between colloids at short distance compared to the particle size, and (iii) the Reynolds number of the flow. We rationalize our results with a simple statistical model. These results have broad implications for practical applications where the interparticle interactions and/or the flow properties can be altered to favor (or prevent) particles retention or clogging such as filtration membranes (or microfluidic devices).