How to control the uniform micro bubbles generation on underwater superaerophobic surface?

Bubbles are an important medium to increase the efficiency of gas/liquid mass transfer. Smaller and more homogeneous bubbles can improve environmental treatment efficiency, microfluidic stability, and medical imaging capabilities. At present, it is still difficult to produce uniform micro bubbles and stably apply them into complex environment. Herein, a strategy of aerating micro bubbles by designing four different structures via laser ablation is proposed. The underwater superaerophobic polyimide (SPI) with micro volcano-like channels has been verified to produce bubbles with a volume of nanoliter. It is attributed to the combination of the micro-nano rough structures covering the surface and the micro-volcanic structure limiting the expansion of bubbles. The SPI with micro volcano-like structure, as a porous aeration film, can make various gases pass, which can be applied to water purification and gas detection. It is also found that the designed SPI with micro volcano-like structure can resist the damage of complex application environments, such as extreme water environments and ultraviolet radiation. As indicated in all the results, the SPI is applicable and flexible. The femtosecond laser can realize high precision and good controllability of the superaerophobic surface, which is difficult for other traditional methods to fabricate micropores. This distinctive membrane provides a new inspiration to design advanced materials for applications in gas transport and collection, wastewater treatment, and chemical reactions. It is also helpful to promote the basic research and applications of micro and nano bubbles generation.