To stick or not to stick... that is the question.
Patrick Tabeling's group in collaboration with his former post-doc, Cesare Cejas, has recently published an article underlying the mechanisms required for particles to adhere (or not adhere) onto surface walls when traveling inside a micro channel.
The physics is particularly rich and the paper, using microfluidics experiments, numerical simulations, and theory demonstrates the various factors at play controlling particle trajectories: hydrodynamic forces, adhesion (van der Waals), diffusion, electrostatic forces, etc.
The roles of these phenomena with respect to one another are summarized in a universal diagram of particle deposition.
For more information, check out the paper published in Physical Review E
C.M. Cejas, F. Monti, M. Truchet, J.-P. Burnouf, P. Tabeling. (2018). "Universal diagram for the kinetics of particle deposition in micro channels." Physical Review E. 98. 062606.