  Superrepellency is a favorable non-wetting situation featured by a
dramatically reduced solid/liquid contact region with extremely low adhesion.
However, drop impact often brings out a notable extension of the contact region
associated with rather enhanced water affinity, such renders irreversible
breakdowns of superhydrophobicity. Here, we report an alternative outcome, a
repeated Cassie-Wenzel-Cassie (CWC) wetting state transition in the microscale
occurs when a drop impacts a two-tier superhydrophobic surface, which exhibits
a striking contrast to the conventional perspective. Influences of material
parameters on the impact dynamics are quantified. We demonstrate that
self-cleaning and dropwise condensation significantly benefit from this outcome
- dirt particles or small droplets in deep textures can be taken away through
the transition. The results reported in this study allows us to promote the
strategy to design functional superrepellency materials.
