Transparent Light‐Driven Hydrogel Actuator Based on Photothermal Marangoni Effect and Buoyancy Flow for Three‐Dimensional Motion

Marangoni‐effect‐driven actuators (MDAs) have the advantages of direct light‐to‐work conversion and convenient operation, which makes it widely researched in the cutting‐edge fields including robots, micromachines, and intelligent systems. However, the MDA relies on the surface tension difference and it only works on the 2D liquid–air interface. Besides, the MDAs are normally pure black due to the light‐absorption material limitation. Herein, a...