Abstract: Gas/liquid separation is a fundamental process in many chemical or biological processes, especially for microfluidic systems, in which microchannel can impede or even stop liquid flowing. Recently, many researches are focused on bubble removal from where they form in order to avoid the above adverse effects occurring. However, the introduction of venting holes will cause the leakage of inner liquid. Superhydrophobic mesh structures can hold water droplets steadily, and its capability of leakage prevention is excellent for mesh with small size. Herein, microscaled and nanoscaled hierarchical structured copper mesh was fabricated by one-step solution-immersion process and it exhibited perfect superhydrophobicity. The component and morphology of the as-prepared sample were characterized by XPS, FTIR and ESEM. FTIR and XPS spectra demonstrate that the aggregates have a chemical composition of Cu[CH3(CH2)12COO]2. The ESEM images clearly show that clusters of continuous flowerlike architectures are formed on the copper mesh substrate. Then, bubble behavior on such special structures was investigated by high-speed camera. It is found that bubbles in water can easily vent out through the superhydrophobic copper mesh, while the case does not happen to hydrophilic copper mesh. These findings will provide a method in designing novel superhydrophobic materials in the near future, which may be developed into an effective degassing plate with bubble capture and distributed venting for microfluidic devices.

Key words: Bubble, Superhydrophobic, Mesh structure, Venting