Figure 2

Flow field and particle deposition. (a) Representative image of the wedge. (b) Temporal variation in wedge area. Internal velocity field of the droplet (measured at \(h/{h}_{i}=0.5\) where h _i : initial droplet height) and corresponding schematic showing particle aggregation (second row) for (c) unconfined case where the radially outward flow results in azimuthally uniform particle deposition (d,e) L _c  = 5 mm; directional flow leads to thicker shell on the open sides; buckling occurs from the wall (thinner) sides (f,g) L _c  = 20 mm; dome shaped structure is obtained due to low evaporation flux. For all cases, φ _o  = 40 wt.%. Red arrows depict the flow directions. Channel walls are depicted by red lines. Inset in (c) shows the evaporation process from nano-menisci. t_e: total time for evaporation. Scale bar equals 500 µm.