Robust adhesion of droplets via heterogeneous dynamic petal effects

Hypothesis:

Bionics and dynamic interface wetting intensely appeal to many research communities due to their unique practical implications. The rose petals had a highly robust dynamic water-retaining capacity under heavy precipitation. We predicted that the roses became more “hydrophilic” at higher Weber numbers.

Experiments:

Fresh rose petals were directly impacted by droplets, and facile artificial petal-like substrates and superhydrophobic substrates were used in the comparative analysis. The wetting dynamics of the droplet (e.g., topography, bounce dynamics, contact time, three-phase contact lines, and oscillations) were investigated when interacting with four selected target substrates.

Findings:

The present work first time investigated the dynamic wetting rule of the sticky superhydrophobic substrates (SSHS). Simulated and experimental investigations confirmed that the unique coupling synergy between the pinning effect and the inhomogeneous micropapillaes resulted in lopsided contact line velocities, which remarkably suppressed the lateral oscillation and rebounding. This may be a new strategy when designing dynamic water-repellent surfaces and open a promising avenue for emerging areas such as super-efficiency energy conversion and harvesting.