Patterning candle soot for light-driven actuator via Marangoni effect

Smart light-driven machines that can be manipulated in a remote, contactless and controlled way are desired for many applications. Although considerable efforts have been devoted to the light-driven devices, challenges still remain in the multifunctional structure design, the development of patternable photothermal materials and precise control. In this report, we demonstrate a facile method to construct smart floating devices by the incorporation of candle soot with designable patterns into PDMS, which can be propelled by light-induced Marangoni effect. The device shows high photothermal conversion capability and photothermal stability. Meanwhile, it realizes multiple movement modes including linear, curvilinear movement and rotational movement by designing asymmetric structures or adjusting the illumination site of light sources. Moreover, the floating actuator can be driven not only by infrared (IR) light, but also by focused sunlight. This work will inspire us to explore great potentials in various fields such as soft robot, sensor, and electricity generator etc.