Strain‐Induced Surface Micro/Nanosphere Structure: A New Technique to Design Mechanically Robust Superhydrophobic Surfaces with Rose Petal‐Like Morphology

Abstract

AbstractA robust surface geometrical structure not only enables a favorable practical application but also leads to a long‐term reliability of superhydrophobic surfaces, and hence it is pivotal to find an effective route to improve the mechanical durability of superhydrophobic surfaces. This study reports a simple magnetron sputtering method to directly construct a robust rose petal‐like copper surface with high water adhesion (petal effect). A stable surface micro/nanosphere topography combining with naturally low surface energy is spontaneously formed by the strain‐induced‐island growth of the copper films during the sputtering process. Further reduced surface energy by fluorosilane, the rose petal‐like surface shows a high water contact angle (≈161.4°), effective adhesion force of ≈154 µN, and no‐loss transportation critical droplet volume of ≈98 µL. In addition, as‐prepared superhydrophobic surfaces exhibit superior mechanical stability according to the thermal shock (−40 °C/90 °C) for ≈500 cycles, water‐impacting test for ≈6 h, and finger touch (≈20 times) as well as tape‐peeling test (≈65 times) without losing superhydrophobicity. This work might provide a novel but simple way to directly and effectively fabricating robust superhydrophobic metallic surfaces for potential industrial applications, and can be easily extended to other metals and alloys.