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

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Ma, Jingcheng

Contributors dc:contributor

• Jacobi, Anthony M
• Miljkovic, Nenad
• Cahill, David G
• Braun, Paul V

• Dropwise condensation
• Hydrophobic coatings
• Droplets
• Durability

Statement dc:rights

• Copyright 2022 Jingcheng Ma

Language dc:language

en, eng

Handle dc:identifier

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

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115812