Adjustable Underwater Gas Transportation Using Bioinspired Superhydrophobic Elastic String

Dynamic and precise manipulation of the gas flow in a liquid environment through a facile and reliable approach is of great importance for directional gas transportation and multiphase chemical reactions. In this research, elastic superhydrophobic strings were prepared by a one-step, non-fluorinated dip-coating strategy. The surface-treatment string demonstrated a good superaerophilicity underwater. By simply elongating or shortening superaerophilic strings, the gas flux underwater was precisely manipulated in a gas-siphon underwater experiment. The result reveals that a large strain of the treated string induces a low gas flow, and a rope woven with more strings results in a larger range of gas flow regulation. The elastic superhydrophobic/superaerophilic string was utilized to adjust the reaction time of carbon dioxide and sodium hydroxide aqueous solution successfully. Furthermore, in a wet oxidation experiment for treating simulated flue gas composed of nitric oxide (NO), nitrogen and oxygen, superhydrophobic and stretched strings with a strain of 200% demonstrated a 7.9% higher NO removal efficiency than that of untreated strings. Interestingly, NO removal efficiency can be regulated by mechanical stretching of gas-conducting strings. We believe that this facile and low-cost approach provides a valid method of on-demand manipulation of the gas flow for underwater gas transportation.