Force Driven Separation of Particles and Drops by Deterministic Lateral Displacement

We present the separation of solid particles and drops in force-driven deterministic lateral displacement (f-DLD), a promising high-throughput continuous separation method in microfluidics. We perform both macroscopic experiments in scaled up systems as well as microfluidic experiments. The solid particles or drops are driven through a square array of cylindrical obstacles and, for some forcing orientations, they migrate in different directions. These experiments demonstrate the separation capabilities —and provide constraints for the design— of f-DLD for particles and drops of multiple sizes. We show that in all cases the trajectories of the particles follow selected locking directions in the lattice and present a simple collision model, based on particle-obstacle repulsive interactions, that accurately describes the trajectories of the particles for all forcing directions. Finally, we also demonstrate that a single line of cylindrical obstacles rotated with respect to the driving force is capable of performing binary separations. Using scaled up models proved to be a succesful approach to capture the behavior of microfluidic systems and test the deterministic limit.