Nonaffine motion of highly polydisperse emulsions in a quasi-2D L-shaped chamber

We investigate the flow of highly polydisperse emulsion droplets confined to a quasi-2D geometry. We produce stable oil-in-water droplets with an average radius of ~40 μm, spanning a size range from ~20 μm to ~200 μm, and a polydispersity index of 0.4. The droplets are driven through a custom-designed L-shaped chamber with height 100 μm. Droplets are forced to rearrange as they navigate around the corner of the L-shaped flow chamber. The nonaffine motion is the difference between the time-and-droplet-averaged flow field and the instantaneous displacements of individual droplets. We observe the largest droplets having distinctly different flow behaviors than the smallest droplets: the smallest droplets frequently have to move around the larger ones, giving the smallest droplets more nonaffine motion. We also study how the nonaffine motion depends on the area fraction of the droplets, ranging from dilute to jammed conditions.