# Micro-Actuators with Light and Magnetism Dual-Control for Maneuverable Movements
## 3 Results and Discussion
### Directional Control and Maneuverability Analysis  
To investigate whether the triangular drive can flexibly change its forward direction, a zigzag maze was built on the liquid surface (Figure 4). Red arrows indicate the direction of laser irradiation and the forward direction of the boat, and white dashed lines indicate the motion trajectory. With changing the laser spot position, the drive was propelled by the asymmetric Marangoni force, and a free and controlled motion in the direction was achieved. It is worth noting that either side of the triangular boat can be used to drive itself forward, so the boat can theoretically be driven in any direction at the two-phase interface. As shown in Figure 4a, the boat was initially placed at the entrance of the maze, and it could walk freely under laser driving. The maze movement was designed as a combination of three straight line movements and two turning points. The boat took 24 s to traverse the first straight line movement to reach the first turning point of the maze. The experimental configuration maintained laser irradiation on a stationary hull reference point, with real-time directional compensation synchronized to propulsion dynamics. This closed-loop implementation enabled gradual vessel navigation through the initial bend, achieving a 36 s completion duration for the curvilinear maneuver. At the first bend, the trajectory of the boat was approximated as an incomplete rotation, with the boat rotating 120 degrees counterclockwise under laser illumination, and the laser spot being fixed on the same point of the drive during this rotational motion. After taking 11 s, the boat went straight ahead to reach the second curve. Then we changed the position of laser irradiation, which directly changed the direction of the boat, so the second turn was faster than the first, taking almost only 3 s, since the boat did not perform any rotational movement during this direction change. In the end, the boat took about 20 s to reach the exit of the maze. The whole maze movement took 92 s, which was undoubtedly a rather long and continuous long-distance movement, the total movement distance of the boat was greater than 180 mm by rough calculation. Despite the variety of photothermal actuators that have been prepared, how to implement the actuators to transport large and bulky objects is also a great technical challenge. In our work, Marangoni thrusters adhered to other objects were prepared using the feature that thin film samples possess excellent adhesion (Figure 4b). Using the Marangoni  
Figure 4: **(a)** A schematic diagram of the zigzag maze track of the boat crossing water surface. **(b)** The motion of the boat’s final position traversing the maze. **(c)** A schematic diagram of the leaf’s forward trajectory driven by the composite film on the water surface. **(d)** The linear motion of the leaf. force generated by the actuators, objects can be driven to walk freely. As an experimental verification, the sample 3 film was cut into a rectangle of 53 mm\({}^{2}\), then it was glued to the end of the leaf to replace the petiole as a drive for transporting. The weight of the leaf used in the experiment was three times that of the pusher. When the pusher at the petiole was irradiated by laser (100 mW, 532 nm), it was rapidly warmed by the light, resulting in a local increase in water surface temperature. Nevertheless, the front of the leaf had no significant temperature change. The temperature gradient led to the Marangoni phenomenon, and the transfer of water drove the leaf to complete the forward motion. The position information during the movement in the figure was extracted from the movie, and the drive position was read once every second. As shown in the video, the thruster transported the leaf by as much as 50 mm under laser illumination during a continuous period of the 60 s. The inset shows the final position of the leaf at the end.