Rapid Bouncing of High-Speed Drops on Hydrophobic Surfaces with Microcavities

Artificial hydrophobic surfaces that can induce rapid drop detachment have many significant engineering applications from self-cleaning to anti-icing. In the present study, we found that hydrophobic surfaces with microcavities can rapidly induce a center-assisted recoil of high-speed impacting drops and subsequently result in an approximately 40% reduction in contact time compared with conventional superhydrophobic surfaces. More intriguingly, the contact time on these surfaces has a rapid descent of over 50% at high-speed impacts compared with that at low-speed impacts, which is due to the rapid bouncing induced by the faster retraction of the liquid lamella triggered by the instability of air bubbles beneath the center of the colliding drops. We believe that these findings will provide a valuable strategy for designing self-cleaning and anti-icing surfaces by minimizing the contact time of high-speed drops.