Fig. 4From: Hierarchical Nanoflowers on Nanograss Structure for a Non-wettable Surface and a SERS SubstrateWetting property of hierarchical surface with CuO nanoflowers for various liquids. a The change of contact angles of various liquids as a function of droplet volume using dropping test. b The average contact angle hysteresis of various liquids as a function of surface tension (droplets of liquids have small CAH of <5° roll on the surface). c Continuous optical images of 7 μL, 25 % ethanol droplet which is rolling on the nanoflower applied hierarchical CuO surface (the total rolling time is 203 ms)Back to article page