Fig. 1.

Droplet impact dynamics. a, b Scheme and sequenced images of a water droplet impacting on a homogeneous hydrophobic and low-adhesive surface. The droplet spreads, homogeneously recedes, and bounces vertically upward from the surface. c Scheme of a water droplet impacting on a low-adhesive substrate with high-adhesive patterns. d Selected snapshots to show the synchronized oblique and side views of the droplet gyrating by impacting on the deliberately-designed adhesion-patterned substrate. After reaching maximum spreading and forming a circular film, the liquid heterogeneously recedes accompanied by rotating in a pinwheel morphology. Four-lobed droplet gyrating in the air is achieved when the droplet departs from the substrate. e Three-dimensional trajectory of the tracking point marked at t = 5.6 ms in d. Time interval between the dots in the curve is 0.33 ms. In the tests above, the droplet diameter is 2.1 mm and the Weber number is 93. Scale bars: 1 mm