Bio‐inspired spontaneous splitting of underwater bubbles along a superhydrophobic open pathway without perturbation

Abstract

Bubbles are pervasive in aqueous media, and on account of numerous advantages of tiny bubbles, efficient bubble splitting is favorable in a wide range of applications. However, underwater bubble splitting faces a lot of challenges because bubbles tend to coalesce during the rising due to the action of buoyancy and surface energy, and the consumption of considerable external energy is needed. Inspired by the bubble bursting phenomenon on the feathers of high‐speed swimming penguins, we proposed a new bubble splitting strategy based on the energy conversion of bubble transportation on superhydrophobic open pathways. A porous superhydrophobic coating was first developed via a bubble‐template assisted fabrication method, which provides hierarchical micro/nanostructures and robust air plastron. Gas bubbles can transport along the superhydrophobic open pathways without perturbation, and split into smaller ones by taking advantage of the potential energy contributed by buoyancy. By controlling the superhydrophobic pathway, the size of the split bubbles can be controlled precisely. We also demonstrated that a bubble splitting device could be applied in underwater reactions where an enhanced gas−liquid mass transfer is desired. This bubble splitting strategy may offer new prospects for underwater bubble manipulation and unfold a potential in many bubble‐involved fields.

Active Droplet Transport Induced by Moving Meniscus on a Slippery Magnetic Responsive Micropillar Array

“…Similarly, a large number of microparticles are randomly distributed on the side surface of pillars. These microstructures increase the roughness and make the surface more hydrophobic and oleophilic. , As can be seen from Figure d, the contact angles of water and silicone oil on the treated surface are 130 and 4°, respectively. Thus, the infusing silicone oil can form a stable slippery structure on the prepared micropillar array.…”

Fluid manipulationviamultifunctional lubricant infused slippery surfaces: principle, design and applications

“…Superhydrophobic surfaces as effective gas carriers facilitate multiphase reactions containing gases. [88][89][90][91] Nevertheless, superhydrophobic properties will be ineffective in humid, petroleum, and high-pressure environments due to the suppression or deterioration of air among micro/nanostructures. When SHB surfaces are underwater for a long time, there is an irreversible Cassie to Wenzel state transition on its surface, i.e., a gradual replacement of the gas by water in the micronano structure, which will make the SHB surface no longer attractive to the gas and lose the ability to manipulate bubbles.…”

Superhydrophobicity‐mediated enhanced enzymatic kinetics and high‐performance bioassays

“…[5][6][7] The incorporation of the rough surface characteristics and suitable chemical modification helps the superhydrophobic substrates limit the contact with the water droplet. [8][9][10] When contacting with aqueous solution, superhydrophobic substrates can capture gas between the liquid and solid phases to generate solid-liquid-air triphase interfaces, where gas can be sufficiently and continuously supplied through the gas diffusion channels present in the micro-nanostructures. In gasinvolved heterogeneous catalytic reactions, such as CO 2 reduction, nitrogen reduction, oxidase catalysis, and fuel cells, the kinetics and selectivity of these sort of reactions could be greatly enhanced by using the triphase interfaces that assembled with porous carbon, nanoporous Cu, carbon fibers, Cu dendrites, and patterned-conducting polymers.…”

“…Since the mechanisms underlying the highly water‐repellency phenomenon of lotus leaves have been identified, 4 a variety of artificial superhydrophobic substrates with a unique ability to manipulate water droplets was developed for cutting‐edge applications such as self‐cleaning, oil–water separation, and controlled drug delivery 5–7 . The incorporation of the rough surface characteristics and suitable chemical modification helps the superhydrophobic substrates limit the contact with the water droplet 8–10 . When contacting with aqueous solution, superhydrophobic substrates can capture gas between the liquid and solid phases to generate solid–liquid–air triphase interfaces, where gas can be sufficiently and continuously supplied through the gas diffusion channels present in the micro‐nanostructures.…”