Figure 8.

(a) The phase diagram of the trap-particle interactions. One-way particle transport requires four conditions including mechanical capture (d* ≥ d*_cap), asymmetric interaction (d* ≥ d*_asymm), physical collision (d* ≥ d*_col), and lateral shift into a capturing stream (d* belonging to the shaded region in Figure 7b). d*_col was omitted for clear view of the regions of the other trap-particle interaction. The green shaded regions satisfy all of those conditions. The row shift fraction of the array is 1/3, and the ratio of inter-trapping blocks gap, h, to inter-barriers gap, g, is 1.5. (b) Theoretical prediction and experimentally validated trap-particle interaction dynamics in the arrays of row shift fraction (ε) of 1/3. Symbols: green triangles () = one-way particle transport, inverted closed red triangles () = trap skipping by bump mode, inverted open triangles () = trap skipping by zig-zag mode , closed circles () = symmetric capturing, and open circles () = symmetric passage. (c) Images of the experimental locations of the particles in one-way particle transport before and after seven fluid oscillations. A group of particles (surrounded by the red-dashed rectangle) in the entry part of the array (Left) was transported to the end region of the array (Right) by one-way particle transport. (d) Experimental positions of particle distribution before (dashed line) and after (solid line) oscillations for different trap-particle interactions: (Top left) one-way particle transport, (Top right) symmetric capturing, (Bottom left) trap skipping in zig-zag mode transport, and (Bottom right) trap skipping in bump mode transport. The diagrams in each graph show detailed trap-particle dynamics. (e) Particle separation using the asymmetric traps. The particle (green) in one-way particle transport was transported faster and further than the particle (red) in the symmetric capturing, resulting in the particle separation.