Dropwise condensation represents the upper limit of thermal transport efficiency for liquid-to-vapor phase transition. A century of research has focused on promoting dropwise condensation by attempting to overcome limitations associated with thermal resistance and poor surface-modifier durability. Here, we show that condensation in a microscale gap formed by surfaces having a wetting contrast can overcome these limitations. Spontaneous out-of-plane condensate transfer between the contrasting parallel surfaces decouples the nanoscale nucleation behavior, droplet growth dynamics, and shedding processes to enable minimization of thermal resistance and elimination of surface modification. Experiments on pure steam combined with theoretical analysis and numerical simulation confirm the breaking of intrinsic limits to classical condensation and demonstrate a gap-dependent heat-transfer coefficient with up to 240% enhancement compared to dropwise condensation. Our study presents a promising mechanism and technology for compact energy and water applications where high, tunable, gravity-independent, and durable phase-change heat transfer is required.

中文翻译：

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微尺度限制和润湿对比可实现增强和可调的冷凝

滴状冷凝代表液相到气相转变的热传输效率上限。一个世纪的研究一直致力于通过克服与耐热性和表面改性剂耐久性差相关的限制来促进滴状冷凝。在这里，我们展示了由具有润湿对比的表面形成的微尺度间隙中的凝结可以克服这些限制。对比平行表面之间的自发平面外冷凝物转移分离了纳米级成核行为、液滴生长动力学和脱落过程，从而使热阻最小化并消除了表面改性。纯蒸汽实验与理论分析和数值模拟相结合，证实了经典冷凝的内在限制的突破，并证明了与滴状冷凝相比，间隙相关的传热系数提高了 240%。我们的研究为紧凑型能源和水应用提供了一种有前途的机制和技术，这些应用需要高度、可调、重力无关和持久的相变热传递。