Figure 1
From: Radial Wettable Gradient of Hot Surface to Control Droplets Movement in Directions
Schematic diagrams of experimental set-up for the fabrication of the wettable gradient and the photographs of the water contact angles.
a) Experimental set-up. Electrolyte level is below the center. The point close to the center has a shorter oxidation time and lower current density. A radial wettable gradient is fabricated with the direction from center to periphery. b) Photographs of the water contact angles along the graphite surface with wettable direction from center to periphery. More oxygen-containing groups are formed on the periphery. c) Electrolyte level is above the center, the radial wettable gradient is in opposite direction, from periphery to center. d) Photographs of the water contact angles along the graphite surface with wettable gradient direction from periphery to center. More oxygen-containing groups are formed on the central parts.
