Micromesh-Covered Superhydrophobic Surfaces for Efficient Condensation Heat Transfer

Condensation is a ubiquitous phase-change phenomenon and has been widely used in energy-intensive industrial applications. By promoting self-propelled droplet jumping, superhydrophobic surfaces offer an avenue to improve condensation heat transfer performance. However, the tendency of condensed droplets to form as pinned states greatly limits its applicability in condensation heat transfer, especially under large surface subcooling. Here, we report the development of a micromesh-covered superhydrophobic surface via a simple fabrication method that allows for high efficiency jumping condensation at small surface subcooling and the continuous droplet suction-enhanced condensation at large surface subcooling. We show that the cooperation of droplet jumping and suction effect can lead to enhanced heat transfer performance throughout the large range of surface subcooling: an 80% higher heat flux at Delta T < 4 K and a 35% higher heat flux at 4 K < Delta T < 30 K compared to dropwise condensation on the state-to-the-art plain hydrophobic surface. The new insights about the cost-effective surface fabrication and the novel condensation modes induced by the integration of droplet jumping and suction can guide the development of new technology for enhancing phase-change heat transfer.