Controlling particle dynamics in dead-end channels via tunable boundary effects

This study examines chemically induced transport mechanisms for colloids in dead-end channels, specifically focusing on diffusiophoresis, which is driven by electrolyte concentration gradients. Within these channels, such gradients not only drive particle motion but also generate fluid flows along the channel walls (diffusioosmosis) in opposing directions. The wall slip velocity generates a parabolic bulk flow competing with the diffusiophoretic motion of the colloidal particles. Different particle delivery patterns can be generated and controlled. The particle velocities in these channels are influenced by the zeta potential of the particles, the contrasting diffusivities of electrolyte cations and anions, and the streaming potential of the walls. Variations in the materials at the dead-end boundaries significantly impact the streaming potential, thus affecting diffusioosmotic behavior. In this talk, I will demonstrate the manipulation of particle dynamics by modifying the wall streaming potential.