Efficient Gas Transportation Using Bioinspired Superhydrophobic Yarn as the Gas-Siphon Underwater

Abstract

Inspired by the gas-trapped mechanism underwater of Argyroneta aquatica, we prepared a superhydrophobic yarn with a fiber network structure via a facile and environmentally friendly method. Attributed to the low surface energy, the superhydrophobic fiber network structure on the yarn is able to trap and transport bubbles directionally underwater. The functional yarn has good superhydrophobic and superaerophilic properties underwater to realize the directional transport of bubbles underwater without being pumped. We designed demonstration experiments on the antibuoyancy directional bubble transportation, which indicated the feasibility in the applications of gas-related fields. Significantly, on further testing, where the superhydrophobic yarn is put into a U-shaped pipe, we obtain a gas-siphon underwater with a high flux. The superhydrophobic fiber structure yarn can trap the gas underwater to enable the self-starting behavior while no manual intervention is used. The gas-siphon can convey gas over the edge of a vessel and deliver it at a higher level without energy input, which is driven by the differential pressure. The relationship between the differential pressure and the volume flux of transport bubbles is investigated. The experimental results show that the prepared superhydrophobic yarn has the advantages of good stability, easy preparation, and low cost in bubble continuous transportation underwater, which provides a novel strategy for the development and application of new technologies such as directional transportation, separation, exhaustion, and collection of gases in water.

The challenges, achievements and applications of submersible superhydrophobic materials

“…64,233,236 Complementary to this, underwater gas transportation becomes essential in many processes, including underwater micro-reactions, water treatment, and selective aeration. [237][238][239][240][241] Whether gases are meant to be delivered to the reaction place or removed away from it, controlling the bubbles pathway is important for process completion. 233,242 Generally, bubble movement is influenced by buoyancy forces, which could make the process less concerning in some cases.…”

“…An issue that open surfaces may suffer from is the resistant buoyancy forces, which intensify when the transportation occurs in the opposite direction of the buoyancy force component. 241 A pipe-like design could provide a solution for this, as such forces get reduced in closed surfaces. This also could be beneficial in cases where physical forces become insufficient for transportation, like transporting large bubble volumes or under high depths.…”

“…This also could be beneficial in cases where physical forces become insufficient for transportation, like transporting large bubble volumes or under high depths. 241 Zhang et al suggested superhydrophobic yarn-like fibres were to be used for this purpose. 241 The resistance-force reduction was indicated by the consistent flow from the injection point to the highest escape point (yarn end), regardless of how the yarn was being shaped.…”

“…241 Zhang et al suggested superhydrophobic yarn-like fibres were to be used for this purpose. 241 The resistance-force reduction was indicated by the consistent flow from the injection point to the highest escape point (yarn end), regardless of how the yarn was being shaped. Moreover, when the yarn is U-shaped with one of the ends being underwater, the gas flow was observed indicating siphon-effect.…”

“…Moreover, when the yarn is U-shaped with one of the ends being underwater, the gas flow was observed indicating siphon-effect. 241 Another system that combines both storage and transporting capabilities was reported by Chen et al 240 as a way to collect and eliminate methane generated under oceans and avoid its release into the atmosphere, as it contributes significantly to the greenhouse effect. [252][253][254] Porous polyurethane sponges were dip-coated by a silica nanoparticles/polystyrene mixture to add the hydrophobic nature.…”