Hierarchical Superhydrophobic Surfaces with Micropatterned Nanowire Arrays for High-Efficiency Jumping Droplet Condensation

Ronggui Yang, Rongfu Wen, Shanshan Xu, Dongliang Zhao, Yung-Cheng Lee, Xuehu Ma

Research output: Contribution to journalArticlepeer-review

131 Scopus Citations

Abstract

Self-propelled droplet jumping on nanostructured superhydrophobic surfaces is of interest for a variety of industrial applications including self-cleaning, water harvesting, power generation, and thermal management systems. However, the uncontrolled nucleation-induced Wenzel state of condensed droplets at large surface subcooling (high heat flux) leads to the formation of unwanted large pinned droplets, which results in the flooding phenomenon and greatly degrades the heat transfer performance. In this work, we present a novel strategy to manipulate droplet behaviors during the process from the droplet nucleation to growth and departure through a combination of spatially controlling initial nucleation for mobile droplets by closely spaced nanowires and promoting the spontaneous outward movement of droplets for rapid removal using micropatterned nanowire arrays. Through the optical visualization experiments and heat transfer tests, we demonstrate greatly improved condensation heat transfer characteristics on the hierarchical superhydrophobic surface including the higher density of microdroplets, smaller droplet departure radius, 133% wider range of surface subcooling for droplet jumping, and 37% enhancement in critical heat flux for jumping droplet condensation, compared to the-state-of-art jumping droplet condensation on nanostructured superhydrophobic surfaces. The excellent water repellency of such hierarchical superhydrophobic surfaces can be promising for many potential applications, such as anti-icing, antifogging, water desalination, and phase-change heat transfer.
Original languageAmerican English
Pages (from-to)44911-44921
Number of pages11
JournalACS Applied Materials and Interfaces
Volume9
Issue number51
DOIs
StatePublished - 2017

NREL Publication Number

  • NREL/JA-5500-70721

Keywords

  • condensation
  • hierarchical nanostructured surface
  • jumping droplets
  • nucleation control
  • spontaneous droplet movement
  • superhydrophobic

Fingerprint

Dive into the research topics of 'Hierarchical Superhydrophobic Surfaces with Micropatterned Nanowire Arrays for High-Efficiency Jumping Droplet Condensation'. Together they form a unique fingerprint.

Cite this