Wetting of ring-shaped surface domains

Wetting of ring-shaped surface domains is studied both theoretically and ex perimentally. The liquid channels covering these domains exhibit a volume-i nduced morphological transition from a homogeneous to a bulge state. The co ntinuous symmetry of the low-volume channels is spontaneously broken by the transition to the high-volume regime. Therefore, an angular displacement o f the bulge does not cost any (free) energy and the corresponding interface deformation represents a Goldstone boson which should be observable for do mains in the micrometer regime.