  Based on energy conservation, we derive a critical condition theoretically
for electrowettinginduced droplet detachment from a hydrophobic curved surface.
Phase diagrams are constructed in terms of droplet volume, viscosity, Ohnesorge
number, friction coefficient at contact line, surface curvature, surface
wettability and electrowetting number. The deduced critical condition offers a
general and quantitative prediction on when the detachment occurs, a criterion
enabling us to gain more insights into how to accurately manipulate the
electrowetting-induced detachment of an aqueous droplet on a curved surface.
The results obtained in this paper also imply that the detachable regimes of
the phase diagrams can be enlarged through increasing droplet volume and
surface curvature, and reducing liquid viscosity, friction coefficient,
Ohnesorge number and wettability of substrates.
