## 3 Results
### Antiwetting Behavior of the Stationary Model
#### 3.1.2 Promotion of Antiwetting by Static Superhydrophobic Surfaces  
When immobile, the superhydrophobic surface can remain dry, unlike in models with hydrophilic surfaces. Due to the high droplet-impact velocity and superhydrophobic surface, the energy loss of the droplet is low. After impact, the droplet still has high kinetic energy, and the low-thickness liquid film can sputter many derived droplets during the retraction stage and then break away from the surface. No \"crown splashes\" [37; 38; 39] were observed (Figure 4a-c) (see details in \"Supporting Movie S2\" in the Supplementary Material).  
The multiple-fusion process of droplets on superhydrophobic surfaces facilitates the derived droplet bounce-off. Theoretically, the behavior of a derived droplet is still dominated by inertia after detaching from the original droplet, and its energy (including kinetic energy and surface energy) must be much lower than that of the original droplet. After the droplet merges with the low-energy-derived droplet (from \(t=1347.96\) to \(1355.29\) ms), the internal energy is converted, the energy of the newly formed droplet is increased through the fusion phenomenon, and a larger high-energy droplet is formed (from \(t=1366.63\) to \(1422.62\) ms), which finally promotes the ejection of all the droplets (see details in Figure S4 in the Supplementary Material). The splitting and detachment behaviors of the droplets significantly reduce the loads caused by the droplet impact and adhesion, and there is no continuous wetting phenomenon on superhydrophobic surfaces. The torque peak measured by the torque sensor was 0.001 Nm, compared with having a hydrophilic sur  
Figure 3: A liquid film develops on the surface of the hydrophilic model as droplets fail to escape from the hydrophilic surface after impact; the crown phenomenon appears as the liquid film continues to accumulate (see more details in “Supporting Movie S1” in the Supplementary Material).  
face (0.008 Nm peak torque), and so the superhydrophobicity reduced the sensor torque measurement by 87.5%, as shown in Figure 4d.  
The \"edge effect\" of the droplet significantly affects the fluid-mass distribution within the droplet and accelerates the solid-liquid separation process (see Figure S5 in the Supplementary Material). For the droplet size \(D_{0}=4.2\) mm, the theoretical contact time [22] is \(t_{c}=2.6\sqrt{\rho D_{0}^{3}/(8\gamma)}=29.45\) ms. At \(t=1754.28\) ms, the liquid on the suspended side was the first to leave the surface, and it took 9.66 ms, which was 67% less than the theoretical contact time (\(t_{c}\)). The remaining droplets on the surface were completely detached from the surface within 17.66 ms (\(t=1762.28\) ms), which was 40% less than the theoretical contact time (\(t_{c}\)).  
Figure 4: Multiple droplets hit a stationary superhydrophobic model; the graph shows the impact-level analysis. As indicated from (**a**–**c**), the impinging droplets break up and bounce off, and the superhydrophobic surface remains dry. (**d**) The superhydrophobic surface significantly weakens the impact force (qualitatively equivalent to torque), and the peak torque is only 1/8 of that of hydrophilic surfaces (see details in “Supporting Movie S2” in the Supplementary Material).