Mechanism of droplet rebound failure induced by temperature difference-driven condensation on superhydrophobic surfaces

Droplet impact behavior on superhydrophobic surfaces plays a crucial role in various thermal management applications, particularly in anti-icing, condensation heat transfer, and moisture control. While extensive studies have focused on freezing-induced adhesion, rebound failure can also occur under non-freezing conditions, where conventional explanations are insufficient. In this study, we systematically conducted droplet impact experiments on cold superhydrophobic surfaces under controlled temperature difference (ΔT) conditions between the droplet and the surface. The results demonstrate that rebound behavior is primarily governed by ΔT rather than the individual temperatures of the droplet and surface. When ΔT exceeds a critical threshold of 15 °C, droplet rebound begins to fail due to intensified interfacial condensation, which forms liquid bridges inside surface microstructures and significantly increases energy dissipation. This temperature-difference-driven interfacial condensation mechanism provides new insights into dynamic wetting failure under thermal gradients, and suggests potential strategies for improving surface design in condensation management, anti-icing, and cold-environment heat exchange systems.