Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

Abstract

In general, the dropwise condensation supported by superhydrophobic surfaces results in enhanced heat transfer relative to condensation on normal surfaces. However, in supersaturated environments that exceed a certain supersaturation threshold, moisture penetrates the surface structures and results in attached condensation, which reduces the condensation heat transfer efficiency. Therefore, when designing superhydrophobic surfaces for condensers, the surface structure must be resistant to attached condensation in supersaturated conditions. The gap size and complexity of the micro/nanoscale surface structure are the main factors that can be controlled to maintain water repellency in supersaturated environments. In this study, the condensation heat exchange performance was characterized for three different superhydrophobic titanium surface structures via droplet behavior (DB) mapping to evaluate their suitability for power plant condensers. In addition, it was demonstrated that increasing the surface structure complexity increases the versatility of the titanium surfaces by extending the window for improved heat exchange performance. This study demonstrates the usefulness of DB mapping for evaluating the performance of superhydrophobic surfaces regarding their applicability for industrial condenser systems.

Solid-like Slippery Surface with Excellent Comprehensive Performance

“…The superhydrophobic surface, designed with inspiration from the lotus, has been widely studied owing to its ability to resist water adhesion. − However, the rough micro/nanostructure that gives the surface superhydrophobicity is susceptible to damage from mechanical shock, leading to a loss of superhydrophobicity. , To date, alternative surfaces have been explored that can easily shed water droplets. Aizenberg et al developed a slippery-liquid-infused porous surface (SLIPS) inspired by Nepenthes, which has gained considerable attention .…”