Out-of-Plane Biphilic Surface Structuring for Enhanced Capillary-Driven Dropwise Condensation

• DOI: 10.1021/acs.langmuir.2c03029
• Publication Date: 2023-01-16T14:47:52Z
• Authors: Luca Stendardo; Athanasios Milionis; George Kokkoris; Christos Stamatop...; Chander Shekhar S...; Raushan Kumar; Matteo Donati; Dimos Poulikakos
• Keywords: Coalescence (physics); Heat transfer enhancement

Rapid and sustained condensate droplet departure from a surface is key toward achieving high heat-transfer rates in condensation, physical process critical to broad range of industrial societal applications. Despite the progress enhancing condensation heat transfer through inducing its dropwise mode with hydrophobic materials, sophisticated engineering methods that can lead further enhancement are still highly desirable. Here, by employing three-dimensional, multiphase computational approach, we present an effective out-of-plane biphilic topography, which reveals unexplored capillarity-driven mechanism droplets. This texture consists diverging microcavities wherein matrix small hydrophilic spots placed at their bottom, is, among pyramid-shaped, superhydrophobic microtextures forming cavities. We show optimal combination angles pyramidal structures achieve deformational stretching droplets, eventually realizing impressive "slingshot-like" ejection texture. Such has potential reduce volume thus enhance overall efficiency, compared coalescence-initiated jumping other state-of-the-art surfaces. Simulations have shown pyramid-shaped microstructures provoke self-ejection low volumes, up 56% lower than straight pillars, revealing promising new microtexture design strategy efficiency water harvesting capabilities.