Zhenda Liu,Dagui Wang,Wei Zhang,Shan Gao,Yang Shen,Zhenxu Shi,Binyang Lu,Dehui Wang,Xu Deng
Material surfaces maintaining a liquid super-repellent is crucial in fields such as anti-fouling, drag reduction, and heat transfer. Superhydrophobic surfaces provide an effective approach but suffer from phase change-induced wetting transitions, hindering their practical applications. In this work, Biphilic armored superhydrophobic surfaces (BASS) are designed by integrating hydrophilic interconnected surface frames with superhydrophobic nanostructures. The hydrophilic top of the frame provides spatial selectivity for condensate droplet nucleation, and superhydrophobic nanostructures enable staying dry. Further growth, coalescence, jumping, and roll-off of the condensate droplets on BASS, show remarkable resistance to phase change-induced wetting transition. It still maintains stable superhydrophobicity when exposed to 100 °C of steam for 240 h, at least two orders of magnitude improvement over traditional superhydrophobic surfaces. Such a designing BASS provides an effective approach to address the phase change-induced wetting transition, thereby extending the practical application in the fields of condensation heat transfer, anti-fouling, and fluid transportation of superhydrophobic surfaces.
The switchable wettability is essential for widespread applications in droplet manipulation, rewritable liquid patterning, fluid carrying, and so forth. However, it remains difficult to achieve the multistimuli-responsive, large-range, and reversible wetting switching especially for liquids with low surface tensions through surface topographical management. Here, we apply a simple and effective template-free self-assembly strategy to fabricate microstructured superamphiphobic surfaces that can reversibly switch the wetting performance for oil by transforming the surface morphology in response to multiple stimuli of magnetic fields and mechanical strains. Notably, the noticeably different wetting switching of oil triggered by different stimuli is demonstrated. The contact angles of hexadecane droplets on the as-prepared surfaces can be reversibly switched between 150 ± 1° and 38 ± 2° in response to mechanical strains. Furthermore, the underlying mechanism of wetting switching has been further elucidated using mathematical models. Interestingly, these switchable surfaces dramatically demonstrate the ability to transport oil droplets, without requiring lubricating liquid films. This work not only achieves the large-range and reversible wetting switching for oil but also opens new avenues for fabricating tunable superamphiphobic surfaces with transformable mushroom-like microstructures that can be easily extended to microstructure-dependent friction or adhesion control and used in other fields.
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