Figure 2.

(a) Results of MATLAB simulation, showing the effect of trap geometry on the development of net Laplace pressure on a 50 μm diameter droplet. A smaller trap size induces earlier constriction of the droplet and accordingly, earlier development of net Laplace pressure. For this simulation, devices with trap size values of 15, 20, and 30 μm at the terminal end of the trap were used. The photograph below the plot shows the corresponding physical position inside the Laplace trap indicated by the x-axis in the plot. (b) Droplets of equal volume elongate to a different extent in different-size traps. The relative elongation of a 50 μm diameter droplet in a 15 μm opening trap is much greater than the elongation of the same size droplet in a 30 μm opening trap. This differential elongation results in the different net Laplace pressure developed in identically sized droplets.