Enhanced Imbibition in Liquid-Infused Coated Microchannels.

Spontaneous capillary imbibition has the potential to improve the performance of many micro and nanodevices since it does not require an external energy source to drive a fluid flow. Despite this advantage, controlling and reducing the friction exerted by the channel walls, which limits the speed of the liquid, remains a challenge. Here, we demonstrate experimentally that infusing the walls of a channel with a liquid lubricant substantially speeds up the imbibition process and reduces the overall viscous friction.

Dynamics and clogging of colloidal monolayers magnetically driven through a heterogeneous landscape.

We combine experiments and numerical simulations to investigate the emergence of clogging in a system of interacting paramagnetic colloidal particles driven against a disordered landscape of larger obstacles. We consider a single aperture in a landscape of immobile silica particles which are irreversibly attached to the substrate. We use an external rotating magnetic field to generate a traveling wave potential which drives the magnetic particles against these obstacles at a constant and frequency tunable speed.