A Comparison Between Self-cleaning Properties Via Rolling Droplets and Condensation on Superhydrophobic Surfaces
Author | : David Leland Miller |
Publisher | : |
Total Pages | : 110 |
Release | : 2017 |
ISBN-10 | : OCLC:1020017382 |
ISBN-13 | : |
Rating | : 4/5 (82 Downloads) |
Book excerpt: Superhydrophobic (SH) surfaces are super water repellent surfaces on which a droplet of water will bead up like a marble and roll off the surface with minimal tilting of the surface. This is caused by the combination of a hydrophobic coating and a rough surface structure. To achieve thermodynamic stability, surface tension of the water pulls the droplet into this shape to minimize the contact area between the droplet and the surface. This creates a high contact angle (CA) between the droplet and the surface and a low sliding angle (SA) of which the droplet begins to roll off the surface. SH surfaces have a variety of potential applications such as drag reduction, anti-icing, improved heat transfer through condensation, and self-cleaning. Numerous reports have been dedicated to exploring the fluid dynamic behavior of water droplets on SH surfaces. This thesis focuses on exploring the self-cleaning properties of SH surfaces. Surfaces contaminated with salt, tobacco, and pollen are cleaned by rolling water droplets over the surface or condensing water on the surface such that when large enough, these droplets roll away due to gravity. SH surfaces explored here are composed of micro-scale or nano-scale rib and cavity structures and and are compared with smooth, hydrophobic surfaces with a similar hydrophobic coating.