Osmotic manipulation of particles for microfluidic applications

Benjamin Abécassis (1) , Cécile Cottin-Bizonne (1) , C. Ybert (1) , A. Ajdari (2) , L. Bocquet (1)

1 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures
2 LPCT - Laboratoire de Physico-Chimie Théorique

Diffusiophoresis, i.e. the movement of macromolecules along a molecular gradient, is shown to be an efficient means to drive particles in microchannels. By using a generic microfluidic setup, we assess the displacement of silica particles under a controlled salt gradient and provide experimental evidence for a strongly enhanced migration process, the amplitude of which depends on the nature of the salt. A theoretical description shows quantitative agreement with the observed experimental features. Furthermore, we describe a set of microfluidic operations such as separation, sorting or focusing of a colloidal assembly which can be efficiently performed using diffusiophoresis.

Domaines: Matière Condensée [cond-mat]

Benjamin Abécassis, Cécile Cottin-Bizonne, C. Ybert, A. Ajdari, L. Bocquet. Osmotic manipulation of particles for microfluidic applications. New Journal of Physics, 2009, 11 (7), pp.75022 - 75022. ⟨10.1088/1367-2630/11/7/075022⟩. ⟨hal-01596126⟩