Hydrophilic–hydrophobic hybrid wettability structures, inspired by desert beetles, have been widely designed to enhance the dewdrops’ migration under subcooled or/and high-humidity environment. However, it is still a challenge to regulate the graded distribution of the hydrophilic micro-regions for condensation applications. In this paper, we design a simple spray method to prepare the superamphiphilic–superamphiphobic hybrid wettability coatings by controlling the mass ratio (MR) of superamphiphobic SiO₂ nano-powder and superamphiphilic gypsum micro-powder. We compare the macroscopical wettability, condensation heat transfer efficiency, frosting delayed time and water harvesting rate to demonstrate the unique advantage of hybrid wettability structures. The results show that the condensation heat transfer efficiency, frosting delayed time and water harvesting rate can be respectively promoted to about 131.50% (MR=1:0.5), 134.74% (MR=1:0.5) and 135.62% (MR=1:1), although their macroscopical wettability will gradually reduce with the MR increase. This work will provide substantial insights into the fabrication of efficient superhydrophilic–superhydrophobic hybrid wettability surfaces for condensation heat transfer, anti-frosting and water harvesting applications.

中文翻译：

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通过混合润湿涂层增强冷凝传热、防结霜和集水

受沙漠甲虫启发的亲水-疏水混合润湿性结构已被广泛设计用于增强露珠在过冷或/和高湿度环境下的迁移。然而，在缩合应用中调节亲水性微区域的梯度分布仍然是一个挑战。在本文中，我们设计了一种简单的喷涂方法，通过控制超双疏SiO _{2的质量比（MR）来制备超两亲-超双疏杂化润湿性涂层。}纳米粉体和超两性石膏微粉体。我们比较了宏观润湿性、冷凝传热效率、结霜延迟时间和集水率，以展示混合润湿性结构的独特优势。结果表明，冷凝换热效率、结霜延迟时间和集水率可分别提升至131.50%左右(先生=1：0.5), 134.74%(先生=1：0.5)和 135.62%(先生=1：1), 虽然它们的宏观润湿性会随着 MR 的增加而逐渐降低。这项工作将为制造用于冷凝传热、防霜冻和集水应用的高效超亲水-超疏水混合润湿性表面提供实质性的见解。