Self-Organization of Microscale Condensate for Delayed Flooding of Nanostructured Superhydrophobic Surfaces
| Autor: | Emre Ölçeroğlu, Matthew McCarthy |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Materials science
Condensation Nucleation Nanotechnology 02 engineering and technology Adhesion Surface engineering 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Chemical engineering Superhydrophilicity Heat transfer General Materials Science Wetting 0210 nano-technology Microscale chemistry |
| Zdroj: | ACS applied materialsinterfaces. 8(8) |
| ISSN: | 1944-8252 |
| Popis: | Superhydrophobic surfaces enhance condensation by inhibiting the formation of an insulating liquid layer. While this produces efficient heat transfer at low supersaturations, superhydrophobicity has been shown to break down at increased supersaturations. As heat transfer increases, the random distribution and high density of nucleation sites produces pinned droplets, which lead to uncontrollable flooding. In this work, engineered variations in wettability are used to promote the self-organization of microscale droplets, which is shown to effectively delay flooding. Virus-templated superhydrophobic surfaces are patterned with an array of superhydrophilic islands designed to minimize surface adhesion while promoting spatial order. By use of optical and electron microscopy, the surfaces are optimized and characterized during condensation. Mixed wettability imparts spatial order not only through preferential nucleation but more importantly through the self-organization of coalescing droplets at high supersaturations. The self-organization of microscale droplets (diameters of25 μm) is shown to effectively delay flooding and govern the global wetting behavior of larger droplets (diameters of1 mm) on the surface. As heat transfer increases, the surfaces transition from jumping-mode to shedding-mode removal with no flooding. This demonstrates the ability to engineer surfaces to resist flooding and can act as the basis for developing robust superhydrophobic surfaces for condensation applications. |
| Databáze: | OpenAIRE |
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