Flexible dual-Janus porous membrane for underwater gas bubbles anti-buoyancy unidirectional transportation

Controllable transportation of bubbles in surfactant or aqueous is very important in daily chemical products, food fermentation, mineral flotation and other fields. However, bubbles are mainly dominated by buoyancy and move upward in solution, which makes the manipulation of bubbles difficult. Although some progress has been made in controlling underwater bubbles, achieving continuous transportation and collection of underwater bubbles without relying on external forces is still a great challenge. To this end, we bionically designed a flexible polydimethylsiloxane (PDMS) porous surface with dual-Janus characteristics. Namely, a porous PDMS membrane integrating structural gradient and wettability gradient realizes the underwater anti-buoyancy unidirectional transportation of bubbles without external force input, and possesses the capability of underwater gas anti-buoyancy transportation and storage. This work provides inspiration and direction for the development and design of underwater gas transportation and storage devices and provides innovative thinking for the implementation of seabed carbon dioxide storage technology.