(492j) Two-Dimensional Diffusiophoretic Banding of Colloidal Particles

Diffusiophoretic processes utilize solute concentration gradients to manipulate colloidal transport for microfluidic applications. The majority of theoretical and experimental investigations study banding of colloids in response to one-dimensional concentration gradients. This limits the design space available to control the localization of colloidal particles. However, recent work has shown that a solute source and a sink can behave like a two-dimensional electric dipole, and enable particle separation based on their surface properties.

In this work, we investigate the effect of spatial arrangement of multiple solute sources and sinks on the banding of diffusiophoretic particles. We perform numerical computations to predict particle trajectories of colloidal particles and observe that an increase in asymmetry of source and sink arrangement enhances banding. We quantify the time required to achieve sufficient banding, explore the effect of geometrical arrangement on the banding structure, and also probe the effect of solute wall permeability on particle trajectories. We find that both the spatial separation of sources and sinks, as well as the asymmetry in geometrical arrangement, control the time required for particle banding.