Bioinspired two-dimensional structure with asymmetric wettability barriers for unidirectional and long-distance gas bubble delivery underwater

Gas bubble manipulations in liquid have long been a concern because of their vital roles in various gas-related fields. To deal with the weakness in long-distance gas transportation of previous works, we took inspiration from the ridgelike structure on Nepenthes pitcher's peristome and successfully prepared a two-dimensional superaerophilic surface decorated with asymmetric aerophobic barriers capable of unidirectional and long-distance gas bubble delivery. For the first time, this process was investigated by in situ bubble-releasing experiments recorded by a high-speed camera and finite element modeling, which demonstrates a kinetic process regulated by the anisotropic motion resistance arising from the patterns. Furthermore, the Nepenthes alata-inspired two-dimensional surface (NATS) was integrated into a water electrolysis system for H2 directional transportation and efficient collection. As a result, the NATS design was proved to be a potential solution for facile manipulation of gas bubbles and provides a simple, adaptive, and reliable strategy for long-range gas transport underwater.