Nanograssed micropyramidal architectures for continuous dropwise condensation

Xuemei Chen, Jun Wu, Ruiyuan Ma, Meng Hua, Nikhil Koratkar, Shuhuai Yao, Zuankai Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

543 Citations (Scopus)

Abstract

Engineering the dropwise condensation of water on surfaces is critical in a wide range of applications from thermal management (e.g. heat pipes, chip cooling etc.) to water harvesting technologies. Surfaces that enable both efficient droplet nucleation and droplet self-removal (i.e. droplet departure) are essential to accomplish successful dropwise condensation. However it is extremely challenging to design such surfaces. This is because droplet nucleation requires a wettable surface while droplet departure necessitates a super-hydrophobic surface. Here we report that these conflicting requirements can be satisfied using a hierarchical (multiscale) nanograssed micropyramid architecture that yield a gobal superhydrophobicity as well as locally wettable nucleation sites, allowing for Ë65% increase in the drop number density and Ë450% increase in the drop self-removal volume as compared to a superhydrophobic surface with nanostructures alone. Further we find that synergistic co-operation between the hierarchical structures contributes directly to a continuous process of nucleation, coalescence, departure, and re-nucleation enabling sustained dropwise condensation over prolonged periods. Exploiting such multiscale coupling effects can open up novel and exciting vistas in surface engineering leading to optimal condensation surfaces for high performance electronics cooling and water condenser systems.

Original languageEnglish
Pages (from-to)4617-4623
Number of pages7
JournalAdvanced Functional Materials
Volume21
Issue number24
DOIs
Publication statusPublished - 20 Dec 2011
Externally publishedYes

Keywords

  • dropwise condensation
  • heterogeneous wettability
  • hierarchical roughness
  • superhydrophobic surface

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics

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