0
Photogallery

Thin Film Condensation Supported on Ambiphilic Microstructures

[+] Author and Article Information
Emre Ölçeroğlu

Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, USA
eolceroglu@gmail.com

Chia-Yun Hsieh

Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, USA
chiayunhsieh@gmail.com

Kenneth K. S. Lau

Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, USA
klau@drexel.edu

Matthew McCarthy

Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, USA
mccarthy@coe.drexel.edu

1Corresponding author.

J. Heat Transfer 139(2), 020910 (Jan 06, 2017) Paper No: HT-16-1723; doi: 10.1115/1.4035580 History: Received November 07, 2016; Revised November 21, 2016

Abstract

Ambiphilic surfaces have been used to support thin liquid films during condensation and imaged using environmental scanning electron microscopy (ESEM). Ambiphilic microstructures (a) are comprised of hydrophilic deep etched silicon micropillars with hydrophobic post tops made of PTFE deposited using iCVD. By restraining the growth of the liquid film using hydrophobic post tops (b), thermal resistance is reduced and heat transfer is increased. During condensation on ambiphilic microstructures the condensate initially fills the post array (b), but then bursts outward to accommodate continued production of liquid (c). This creates a low contact angle droplet on the surface (c), and could lead to complete flooding and decreased performance. With the addition of hydrophilic nanostructures to the micropost array (d), ambiphilic hierarchical structures have been fabricated with dedicated burst sites (e). During condensation the structures maintain a thin liquid film and excess liquid emerges from the burst sites as highly mobile spherical droplets (e). This maximizes the thin film area available for vapor-to-liquid phase change while minimizing thermal resistance across the condensate layer. Scale bars: (a) 5 µm, (b,c) 50 µm, (d) 2 µm, and (e) 25 µm.

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