- Kyoo-Chul (Kenneth) Park
- Doctoral Candidate, Mechanical Engineering
- Project: A Study of Static and Dynamic Robustness of Hydro/Omniphobic Surfaces
- co-advised by Gareth McKinley, Dept. of Mechanical Engineering
- M.S. Mechanical Engineering, Massachusetts Institute of Technology, 2010
- B.S. Mechanical & Aerospace Engineering, Seoul National University, 2008
- Email: kpark@mit.edu
- Phone: (617) 253-0273
- Office: 3-249
Research Summary
Liquid droplets in the Cassie-Baxter state form liquid-air interfaces
that are not flat but distorted due to pressure differences across the
interfaces between the asperities. These distorted interfaces play an essential
role in the transition from the composite Cassie-Baxter state to the
fully-wetted Wenzel state and in the determination of the robustness of the
composite state. As well as the static pressure difference due to the
We have first investigated the shape of distorted liquid-air interfaces and their transition conditions experimentally by using droplets of various low surface tension liquids on millimeter-sized re-entrant surface topography. For the dynamic pressure difference, we proposed a modified water hammer pressure formula and compared with the experiment using a high speed camera. The static experimental results by using three dimensionally printed millimetric structures are in good agreement with our newly-developed finite element simulations. These three-dimensional simulations of the interfacial shape provide a predictive tool for the robustness of a wide range of proposed micro-texture in terms of the breakthrough pressure at which the distorted liquid-air interface infiltrate into the space between asperities and the droplet transitions to the Wenzel state. The dynamic experimental results open a broad avenue to a novel approach to delve into the dynamic breakthrough pressure of droplets of a variety of liquids.
