Magnetoresponsive Tubular Actuators for Stable Bubble Transportation

Stable bubble transportation under a disturbed liquid is crucial for wide-ranging applications from energy collection to gas-related reactions. Despite smart open superwetting surfaces being widely used as bubble delivery systems, it is arduous to transport bubbles under a disturbed liquid with a violent vertical flow and spiral flow. Here, a transparent magnetoresponsive tubular bubble actuator (MTBA) is demonstrated to achieve stable bubble transportation. With the assistance of moving magnets and its instantaneous deformation, the MTBA achieves a high bubble delivery speed (35 mm s-1) and the ability to transport large-sized bubbles (up to 200 μL). Moreover, owing to the powerful transportation capacity, bubbles can be effectively transported in an antibuoyancy direction and in special-shaped MTBAs, like arc-, S-, and step-shaped MTBAs. Compared with the traditional open platforms, this MTBA possesses unique superiority in terms of anti-interference stability under disturbed liquid, transportation distance, transportation speed, and maximum bubble size. These unique characteristics of MTBAs enable the design of a smart bubble microrobot and a circuit switch under disturbed liquid. This promising MTBA is expected to be applied to bubble-related applications of sensors, energy, catalytic reactions, and microfluidics with low surface tension.