Self‐Driving Underwater “Aerofluidics”

Abstract

Here, the concept of “aerofluidics,” in which a system uses microchannels to transport and manipulate trace gases at the microscopic scale to build a highly versatile integrated system based on gas‒gas or gas‒liquid microinteractions is proposed. A kind of underwater aerofluidic architecture is designed using superhydrophobic surface microgrooves written by a femtosecond laser. In the aqueous medium, a hollow microchannel is formed between the superhydrophobic microgrooves and the water environment, which allows gas to flow freely underwater for aerofluidic devices. Driven by Laplace pressure, gas can be self‐transported along various complex patterned paths, curved surfaces, and even across different aerofluidic devices, with an ultralong transportation distance of more than 1 m. The width of the superhydrophobic microchannels of the designed aerofluidic devices is only ≈42.1 µm, enabling the aerofluidic system to achieve accurate gas transportation and control. With the advantages of flexible self‐driving gas transportation and ultralong transportation distance, the underwater aerofluidic devices can realize a series of gas control functions, such as gas merging, gas aggregation, gas splitting, gas arrays, gas‒gas microreactions, and gas‒liquid microreactions. It is believed that underwater aerofluidic technology can have significant applications in gas‐involved microanalysis, microdetection, biomedical engineering, sensors, and environmental protection.

Bubble Unidirectional Transportation on Multipath Aerophilic Surfaces by Adjusting the Surface Microstructure

“…Since the transport channel w is not narrow enough, the bubble injected at region 1 forms an asymmetric bulge instead of a hemisphere, which can lead to asymmetry of the contact line. , From a forced perspective, the asymmetric bubble experiences three primary forces in the horizontal direction (Figure d): the Laplace force ( F L ), the hysteresis resistance force ( F H ), and the drag force ( F D ). With the synergistic effect of the driving force F L and the surface energy release, the bubble can overcome the resistance and transport forward.…”

“…The width of the transport channel also has an important influence on the fluid transport behavior. 39,40,48 Figure 8a,b shows the transport behavior of bubbles on a binary system Figure 7. Effect of the inclination angle on the bubble behavior on the surface corresponding to Model I.…”

“…The inclination angle of the bubble manipulator has been demonstrated to have a significant effect on the gas transportation performance. 40 For a superaerophilic surface that enables self-driven bubble transport when placed horizontally, we consider that the influence of the inclination angle on bubble transport behavior should be consistent with that reported in the literature. Therefore, we will not repeat this factor.…”

Three-dimensional patterning of MoS2 with ultrafast laser

“…Pulsed laser processing, with the advantages of high precision, maskless, controllability, and reproducibility, is broadly used to manufacture microstructures, submicron patterns, and 3D devices. 27–37 Ultrafast laser fabrication is attracting attention in optimizing the physical or chemical properties of 2D materials. 38,39 Laser processing, which modifies the surfaces of 2D materials into different structures, can controllably induce defect generation and chemical modification, resulting in lattice distortion and morphology changes, without losing the integrity of the materials.…”

Transforming Droplets into Liquid Films in Nanochannels under Rotating Electric Fields Studied by Molecular Dynamics

“…The formation of a liquid film pinned in channels by stretching polar liquids via electric fields can be developed as a simple and controllable liquid valve, which provides a new method for achieving precise control in micro/nanofluidic technology. Such liquid films are important for devices such as micro- and nanosensors and in electronic cooling, gas transport and separation, biochemical analysis, etc. − …”