University of Illinois Urbana-Champaign

Fundamental studies of hydrophobic thin film durability and degradation mechanisms during dropwise condensation of steam

Ma, Jingcheng

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MA-DISSERTATION-2022.pdf

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https://hdl.handle.net/2142/115812

Description

Title
Fundamental studies of hydrophobic thin film durability and degradation mechanisms during dropwise condensation of steam
Author(s)
Ma, Jingcheng
Issue Date
2022-04-20
Director of Research (if dissertation) or Advisor (if thesis)
  • Miljkovic, Nenad
  • Cahill, David G
Doctoral Committee Chair(s)
Miljkovic, Nenad
Committee Member(s)
  • Braun, Paul V
  • Jacobi, Anthony M
Department of Study
Mechanical Sci & Engineering
Discipline
Mechanical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Dropwise condensation
  • Hydrophobic coatings
  • Droplets
  • Durability
Abstract
Steam condensation directly affect the energy efficiency of steam power plants that produce 70% of the global electricity baseload. Enhancement in condensation heat transfer has the potential to increase the energy efficiency of these steam power plants by up to 2%, demonstrating a key potential impact on the global energy landscape as well as our carbon footprint. Dropwise condensation on hydrophobic thin films (~100 nm-thick) has the potential to achieve remarkable heat transfer. However, the lack of durability of these thin films has limited applications for a century. Although degradation due to steam condensation has been described as ‘blistering’, no satisfactory insight exists capable of elucidating the driving force for film delamination. This dissertation focuses on designing thin and robust hydrophobic coatings for long-term dropwise condensation. We begin by investigating two mechanisms of coating failure: 1) microscopic condensation-induced blistering, and 2) mesoscopic capillary peeling. We revealed the important role of coating adhesion and pinhole defects on coating’s durability. The findings were leveraged to design, develop, and demonstrate two classes of durable and thin hydrophobic coatings materials: 1) ultra-thin, self-healing dynamic polymer networks that resists pinhole defects, and 2) lipid-like high adhesive coating interfaces, which prevent coating delamination by well-designed van der Waals interaction between the coating and the substrate. The techniques and insights presented here will inform future work on polymeric thin film and enable their durable design for dropwise condensation and a variety of other applications.
Graduation Semester
2022-05
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/115812
Copyright and License Information
Copyright 2022 Jingcheng Ma

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