Biomimetic Mechanoswitchable Interfaces for High-Performance Spatial Gas Bubble Maneuvering.

The on-demand manipulation of gas bubbles in aqueous ambient environments is fundamental to many fields such as microfluidics and biochemical microanalysis. However, most bubble manipulation strategies are limited to restricted locomotion on the confined surfaces without spatial convenience of transport. Herein, we report a kind of biomimetic bubble manipulator with mechanoswitchable interfaces (MSIs), featuring the advantages of parallel bubble control and spatial maneuvering flexibility. By the synergic action between Janus aluminum membrane and superaerophilic microfiber array, the gas-MSI interfacial adhesion can be reversibly switched to achieve capturing/releasing underwater bubbles. Moreover, the adhesion force of MSI can be readily tuned by diverse experimental parameters including surface roughness, fiber number, diameter, and spacing of the neighboring microfibers, which are further systematically investigated. Relying on this mobile platform, we demonstrate a series of powerful applications including bubble parallel control, bubble array regrouping, arbitrary bubble transport and even manipulating underwater solids through bubbles, which are otherwise challenging for conventional approaches. We envision that this versatile platform will bring new insights into potential applications, such as cross-species sample control and handheld gas microsyringe.