Fig. 2

Fabrication and manipulations of droplets on MDCs. a Schematic illustration of laser fabrication process of DMC. b A typical PMMA template fabricated via DLW; c A PDMS overpass structure fabricated via soft lithography; d A superhydrophobic overpass emboss fabricated after laser modification; e A SEM image of DMC. Plenty of nanostructures make DMC superhydrophobic. The contact angle of water droplet is 152°. Bar is 500 nm. f A moving-path assignment chip that made of a “L” shape channel jointed with three branches. Droplets (10.0 μL) released from Height-1, Height-2, Height-3, are assigned to Channel-a, Channel-b, Channel-c, respectively. g A moving-path assignment chip made of an embossed tunnel and a “L” shape branch. Drop-1 (20.0 μL), whose diameter (3.4 mm) is much larger than the width (W, 2 mm) of the tunnel, is pushed to Channel-a; Drop-2 (10.0 μL), whose diameter (2.7 mm) is slightly larger than W, is squashed and assigned to Channel-b. Cross-sections of the tunnel with a 20.0 μL or 10.0 μL droplet are inserted at the bottom corners to further illustrate the size comparison. h A droplet replacement chip made of a sunken groove with two protuberant pillars. Moving Drop-2 collides and replaces stationary Drop-1 without merging. A model and a physical image are inserted on the top. i Cross-sections of an overpass chip made of opposite slopes. Drop-2 jumps over Drop-1 along the white dotted line, from Slope-1 to Slope-2. Inserted images are top view of the jump process. The scale bar is 3 mm. Detail calculations are shown in Supplementary