Bulrush Leaf Superhydrophobicity

August 13, 2018

SuperHydro_EPOD (5)August 2018 Viewer's Choice

Photographer: Greg Parker
Summary Author: Greg Parker 

We had unusually hot weather here in the U.K. in late June and early July (2018), and as a result I had to go out most evenings with a hose to prevent my wife's garden plants from perishing. I noticed that Bulrush leaves (cattails) were superhydrophobic, so decided to capture this effect using a macro lens -- shown above. Superhydrophobic or ultrahydrophobic surfaces are extremely challenging to wet since the contact angles of a water droplet on such a surface exceeds 150 degrees. Note that hydrophobic surfaces have contact angles greater than 90 degrees. Water droplets landing on superhydrophobic materials, including plant leaves, may bounce several times before alighting.

Photo details: Canon 5D MkII camera; manual setting; 1/250th-second exposure; f 25; ISO100; ring-flash at +3.