Hydrophobic coatings with low thermal resistance promise a significant enhancement in condensation heat transfer performance by promoting dropwise condensation in applications including power generation, water treatment, and thermal management of high-performance electronics. However, after nearly a century of research, coatings with adequate robustness remain elusive due to the extreme environments within many condensers and strict design requirements needed to achieve enhancement. In this work, we enable long-lasting condensation heat transfer enhancement via dropwise condensation by infusing a hydrophobic polymer, Teflon AF, into a porous nanostructured surface. This polymer infused porous surface (PIPS) uses the large surface area of the nanostructures to enhance polymer adhesion, while the nanostructures form a percolated network of high thermal conductivity material throughout the polymer and drastically reduce the thermal resistance of the composite. We demonstrate over 700% enhancement in the condensation of steam compared to an uncoated surface. This performance enhancement was sustained for more than 200 days without significant degradation. Furthermore, we show that the surfaces are self-repairing upon raising the temperature past the melting point of the polymer, allowing recovery of hydrophobicity and offering a level of durability more appropriate for industrial applications.

中文翻译：

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聚合物注入的多孔表面可形成坚固，导热，自修复的涂层，以实现逐滴冷凝

具有低耐热性的疏水性涂层通过促进在发电，水处理和高性能电子设备的热管理等应用中的逐滴凝结，有望显着提高凝结传热性能。但是，经过近一个世纪的研究，由于许多冷凝器内的极端环境以及实现增强所需要的严格设计要求，具有足够坚固性的涂料仍然难以捉摸。在这项工作中，我们可以通过以下方式实现持久的凝结传热通过将疏水性聚合物Teflon AF注入多孔纳米结构表面来进行逐滴冷凝。这种注入了聚合物的多孔表面（PIPS）使用了纳米结构的大表面积来增强聚合物的附着力，而纳米结构在整个聚合物中形成了高导热率材料的渗滤网络，并大大降低了复合材料的热阻。与未经涂层的表面相比，我们证明了蒸汽冷凝的提高了700％以上。这种性能增强可以持续200天以上，而不会出现明显的性能下降。此外，我们表明，当温度升高到聚合物熔点以上时，表面会自动修复，从而恢复疏水性并提供更适合工业应用的耐久性。