Superaerophilic Wedge-Shaped Channels with Precovered Air Film for Efficient Subaqueous Bubbles/Jet Transportation and Continuous Oxygen Supplementation

Abstract

Pumpless and directed gas transportation in aqueous environments has promising application prospects in various domains. So far, researches on gas transportation based on superaerophilic channels are limited to the transportation of fewer bubbles with low transportation velocity. How to enhance the transportation velocity and realize the transportation of a large quantity of bubbles (especially for gas jet) for practical applications remain unclear. Here, a half-open wedge-shaped channel with subaqueous superaerophilicity is fabricated, which demonstrates excellent bubble affinity and can realize the pumpless and directed bubble transportation. It is proposed that a Laplace force is the main driving force during the transportation and the magnitude of the force is influenced by both the wedge angle of the channel and geometric parameters of the bubble whereas the direction of the force is determined by the orientation of the channel. By applying a precovered air film on the subaqueous superaerophilic wedge-shaped channel, bubbles demonstrate a higher transportation velocity. Additionally, the prepared channel shows an outstanding affinity to oxygen jet at high flux, which can be utilized to transport oxygen for continuous subaqueous oxygen supplementation.

Controlling water adhesion on superhydrophobic surfaces with bi-functional polymers

“…Indeed, nature exploits surface wettability to reduce/increase contact with water in various intriguing ways, for example, to walk on water surfaces or to see clearly in foggy environments. All these effects are implicitly linked to the specific surface chemistry and surface structuring as previously noted by Wenzel [7] and Cassie-Baxter [8], and intensely studied by other research groups [9][10][11][12][13][14]. Namely, wettability on a solid surface is explained with the equations of Wenzel [7] (cos θ = rcos θ Υ , where r is a roughness parameter and θ Υ is the Young's angle) and Cassie-Baxter [8] (cos θ = f cos θ Υ + f -1, where f is the solid fraction and (1 -f) is the air fraction).…”

“…There are some promising applications that utilize superhydrophobic surfaces and water adhesive properties. For example, gas-transportation in aqueous media [12,13] and water-oil separation [6] employ superhydrophobic/low water adhesive surfaces, and water harvesting systems [22] make use of parahydrophobic surfaces. A range of different biological systems show how fundamental the control of water adhesion is in nature.…”

Nature-Inspired Superwettability Achieved by Femtosecond Lasers

“…Therefore, the lotus leaves show underwater superaerophilicity. Inspired by lotus leaves, underwater superaerophilicity can be easily obtained by producing micro/nanostructures on a hydrophobic (lowsurface-energy) substrate [93,[196][197][198][199]. The materials with underwater superaerophilicity have a remarkable ability to absorb and capture gas bubbles underwater.…”

Sandwiched meshes with superwettability for oil/water separation and heavy metal ion absorption

“…To overcome the oily wastewater problem, a mesh with special wettability such as superhydrophobic–superoleophilic (SHB‐SOL) or superhydrophilic–underwater superoleophobic can be used for oil/water separation 23–31 . In recent decades, many researchers have focused on the preparation of novel materials with extreme wettability for wide applications 32–35 . Feng et al first reported a novel film with SHB‐SOL that was fabricated by constructing microsurface–nanosurface from polytetrafluoroethylene emulsion for an efficient separation of diesel and water 36 .…”

“…[23][24][25][26][27][28][29][30][31] In recent decades, many researchers have focused on the preparation of novel materials with extreme wettability for wide applications. [32][33][34][35] Feng et al first reported a novel film with SHB-SOL that was fabricated by constructing microsurfacenanosurface from polytetrafluoroethylene emulsion for an efficient separation of diesel and water. 36 Pan et al 37 presented an SHB-SOL copper mesh by immersing in aqueous solution of NaOH and K 2 S 2 O 8 and afterward modification with n-dodecanethiol; it demonstrated that this mesh can separate water and hydrophobic solvents with high efficiency.…”