Emerging Advances in Femtosecond Laser‐Designed Underwater “Aerofluidic” Systems: Concept, Design Principle, and Potential Applications

Abstract Traditional microfluidic technology predominantly focuses on the actuation, transport, and manipulation of liquids, whereas the manipulation of gases at the microscale has received limited attention. Analogous to liquid microfluidics, the emerging field of “aerofluidics” focuses on the precise control and manipulation of tiny gases at microscopic scales, enabling the creation of highly integrated systems through gas‐gas or gas‐liquid interactions. This review systematically summarizes the fundamental concepts, design strategies, and achieved functions and applications of underwater aerofluidics, with femtosecond laser microfabrication serving as a key illustrative example. First, the fundamental theory of surface wettability is presented as the relevant background. Additionally, femtosecond laser microfabrication and its application in the design of surface superwettability and macroscopic bubble manipulation are introduced. Then, strategies for designing 2D and 3D underwater aerofluidic structures, as well as the physical mechanism of self‐driven gas transport, are discussed. The next section shows a variety of gas manipulation functions and applications achieved on the designed underwater aerofluidic systems, including gas merging, gas accumulation, gas division, gas patterning, and gas‒gas/gas‒liquid microreactions. Finally, the current progress, existing limitations, and future development directions in this emerging field are summarized and discussed.