Vapor condensation is a well-known phase-change phenomenon observed in nature as well as in different industrial applications. In practical condensation systems, the existence of non-condensable gases (NCG) arising from the leaks, working fluid, or chemical reaction could significantly reduce the condensation heat transfer rate due to the additional thermal resistance offered by the NCG diffusion layer. Superhydrophobic surfaces with low hysteresis can efficiently drain off the condensate and rejuvenate the nucleation sites. However, the main drawback of these surfaces is the lower nucleation rate. The interplay of multiple phenomena such as nucleation, coalescence, and vapor diffusion from the NCG diffusion layer makes the condensation phenomena complex in the presence of NCG. Therefore, understanding the heat-transfer performance of low contact angle hysteresis superhydrophobic surfaces in the NCG environment is crucial for practical applications.

In this work, we fabricated three types of superhydrophobic surfaces by coating, using three different hydrophobic agents on a hierarchical metallic surface fabricated by a facile approach. We have shown that the fabricated superhydrophobic surfaces exhibit almost similar macroscopic wettability (contact angle and contact angle hysteresis) and average roughness; however, condensation behavior on these surfaces and the heat transfer performances were different. The condensation rate on different surfaces under various environmental conditions was compared. The key findings from this study can have implications for the development of engineered surfaces for atmospheric water harvesting, anti-icing, and other phase-change heat transfer applications