Using Anisotropic Micro-Scale Topography to Manipulate the Wettability of Aluminum and Reduce the Retention of Water

Water droplets placed on a micro-grooved aluminum surface using a micro-syringe exhibit significantly increased apparent contact angles, and for water condensed onto an inclined, micro-grooved surface, the droplet volume at incipient sliding is reduced by more than 50% compared to droplets on a surface without micro-grooves. No chemical surface treatment is necessary to achieve this water repellency; it is accomplished solely through the anisotropic surface topography. The droplet geometry shows an elongated base contour relative to a surface without micro-grooves, and discontinuities in the three-phase contact line are also introduced by the grooves. A mechanistic model is presented for predicting the critical droplet size on micro-grooved surfaces. This model extends earlier work by accounting for the droplet geometry and contact-line changes caused by the micro-grooves. The model is validated through comparisons of predicted to measured critical droplet sizes, and it is then used to provide guidance for the development of surfaces with enhanced water drainage behavior. The micro-structured surfaces introduced in this work are proposed for use in air-cooling and dehumidifying applications, but they may have other applications where the management of liquids on a surface is important.

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

2015

Author dc:creator

• Sommers, Andrew David

Contributors dc:contributor

• Jacobi, Anthony M.

• Engineering, Mechanical

Language dc:language

eng

Identifier

(MiAaPQ)AAI3290385

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83890