2009-11-29

Superhydrophobic Materials

clipped from en.wikipedia.org
Superhydrophobe

Superhydrophobic surfaces such as the leaves of the lotus plant have surfaces that are highly hydrophobic, i.e., extremely difficult to wet. The contact angles of a water droplet exceeds 150° and the roll-off angle is less than 10°.[1] This is referred to as the Lotus effect.

The Physical Basis

To understand the physics behind the Lotus-Effect, one has to take a look the
forces that act upon a drop of liquid on a surface.


A droplet on a hydrophilic rough surface seems to sink into the gaps


A droplet on a rough hydrophobic surface sitting on the spikes

Self-Cleaning Properties
clipped from www.ornl.gov

 superhydrophobic materials
Left to right: Water on a lotus leaf; Surface microstructure of the lotus leaf; ORNL "Nano-
Cones" on glass.

clipped from www.youtube.com

Super hydrophobic substances

clipped from video.google.com
Axisymmetric droplet impinging on a hydrophobic surface
clipped from www.youtube.com

Hydration Shell Dynamics of a Hydrophobic Particle

clipped from medtechinsider.com
Some insect wings, for example, are superhydrophobic, which is the combined result of their chemistry and the detailed nanoscale structures on their surface.
IC_Gomphidae_wing
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Sources:
  1. Superhydrophobe - Wikipedia, the free encyclopedia
  2. The Lotus Effect
  3. Advanced Materials: Superhydrophobic Materials
  4. YouTube - Super hydrophobic substances
  5. Axisymmetric droplet impinging on a hydrophobic surface
  6. YouTube - Hydration Shell Dynamics of a Hydrophobic Particle
  7. medtechinsider » Blog Archive » Self-Cleaning Silicone Gel Could Open New Possibilities for Medical Diagnostics
Related:
  1. Science Centric | News | Self-cleaning silicone gel insect wings
  2. Super Water Repellent, Superhydrophobic, Material from ORNL Easy to Fabricate and Uses Inexpensive Base Materials
  3. New Super-Hydrophobic Material Could Revolutionize the Water Repellent Market - Associated Content - associatedcontent.com