0
research-article

How Nanostructures Affect Water Droplet Nucleation on Superhydrophobic Surfaces

[+] Author and Article Information
Abulimiti Aili

Department of Mechanical and Materials Engineering, Masdar Institute of Science and Technology, P. O BOX 54224, Abu Dhabi, United Arab Emirates
aaili@masdar.ac.ae

Qiaoyu Ge

Department of Mechanical and Materials Engineering, Masdar Institute of Science and Technology, P. O BOX 54224, Abu Dhabi, United Arab Emirates
qge@masdar.ac.ae

TieJun Zhang

Department of Mechanical and Materials Engineering, Masdar Institute of Science and Technology, P. O BOX 54224, Abu Dhabi, United Arab Emirates
tjzhang@masdar.ac.ae

1Corresponding author.

ASME doi:10.1115/1.4036763 History: Received September 14, 2016; Revised May 01, 2017

Abstract

Nucleation is the first stage of phase change phenomena including condensation on nanostructured superhydrophobic surfaces. Despite plenty of theoretical studies on the effect of nanostructures density and shape on water droplet nucleation, not many experimental investigations have been reported. Here we show both experimentally and theoretically that a moderate increase in the nanostructures density leads to a subsequent increase in the nucleation density of water droplets because of the decreased energy barrier of nucleation in cavities between the nanostructures. Specifically, we observed droplets aligning in regions with denser nanostructures. And, the droplet number density and average volume of the aligned droplets in these regions were larger than in surrounding areas. However, the nucleation in cavities caused the initial pinning of droplets base into the nanostructures, forming a balloon-like, slightly elongated droplet morphology. The dewetting transition from the pinned Wenzel state to the unpinned Cassie state was predicted by quantifying the aspect ratio of the height and diameter of droplets ranging from 3 µm to 30 µm. Moreover, the coalescence-jumping of condensate droplets was followed by a new cycle of droplet nucleation in a linear manner on an emptied region. These findings offer guidelines for designing enhanced superhydrophobic surfaces for water and energy applications.

Copyright (c) 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In