Spontaneous Cargo Transport via Sliding Bubbles on a Superhydrophobic Wire

The transportation and carrying behavior of underwater bubbles have been widely used for an underwater microactuator, cargo displacement assembly, and drug delivery. This study explores a method for underwater cargo transportation using sliding bubbles as a vehicle with directionally guided superhydrophobic wires. By exploitation of the adhesion between superhydrophobic surfaces and bubble interfaces, a bubble is able to transport a superhydrophobic O-ring along a superhydrophobic wire, effectively delivering the O-ring to the water surface. The capability of the bubble-driven O-ring to rise along superhydrophobic wires was systematically evaluated and analyzed, focusing on the two configurations formed by the bubbles and O-rings. Additionally, we identified the conditions necessary for the successful rising of bubbles and O-rings of varying sizes as well as their trajectories and rising velocities. Through an analysis of the relationship between the Ohnesorge number and Reynolds number, the kinetic characteristics of the bubble-carrying O-ring are elucidated. Furthermore, the applications of bubble transportation in cyclic actuation and underwater data collection are substantiated. This strategy offers a highly reliable method for underwater information transmission and patrol as well as potential applications in bubble transportation.