Figure 4

a-e, Optical images of droplet driven on DMRWs.

Surface of DMRWs is included 9 micro-walls marked from number 1 to number 9. As the magnet getting closer, the tilt angles increase. The discrepancy between advancing contact angle (ACA) and receding contact angle (RCA) increase induced by the tilt effect and CA hysteresis. The CA discrepancy increases from 0° to 7° (see the inset of a, b, c, d and e, the left frame is RCA and the right frame is ACA). f–h, Illustration of (a), (c) and (e). The solid red line represents the three-phase contact line, the dotted yellow and black line frame represent the receding and advancing contact area, respectively.