Wettable Slippery Surfaces. Self-cleaning Effect and Mechanism

K-Y Law
Research and Innovative Solutions,
United States

Keywords: self-cleaning, slippery surface, wetting, contact angle, sliding angle, superhydrophobicity

Summary:

The phenomenon of self-cleaning displayed by the Lotus leaf and many other plant and insect surfaces has attracted tremendous attention recently. Self-cleaning surface is usually superhydrophobic and non-wettable, and is characterized by a very large contact angle and a small sliding angle. Wettable surfaces, on the other hand, are characterized by small contact angles (e.g., ≤50 degree). It is very uncommon to have surfaces that are highly wettable and slippery (sliding angles ≤10 degree) at the same time. In this report, recent work on wettable, slippery surfaces from the author’s lab as well as others is reviewed. The fundamental mechanism leading to the slipperiness, despite of the small contact angles, is proposed and discussed. The self-cleaning effect exhibited by these uncommon surfaces is reported.