Li Zhiwei, Ye Zuyang, Han Lili, Fan Qingsong, Wu Chaolumen, Ding Deng, Xin Huolin L, Myung Nosang Vincent, Yin Yadong
Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA.
Department of Physics and Astronomy, University of California-Irvine, Irvine, CA, 92697, USA.
Adv Mater. 2021 Jan;33(3):e2006367. doi: 10.1002/adma.202006367. Epub 2020 Dec 9.
Photothermal actuators have attracted increasing attention due to their ability to convert light energy into mechanical deformation and locomotion. This work reports a freestanding, multidirectional photothermal robot that can walk along a predesigned pathway by modulating laser polarization and on-off switching. Magnetic-plasmonic hybrid Fe O /Ag nanorods are synthesized using an unconventional templating approach. The coupled magnetic and plasmonic anisotropy allows control of the rod orientation, plasmonic excitation, and photothermal conversion by simply applying a magnetic field. Once the rods are fixed with desirable orientations in a bimorph actuator by magnetic-field-assisted lithography, the bending of the actuator can be controlled by switching the laser polarization. A bipedal robot is created by coupling the rod orientation with the alternating actuation of its two legs. Irradiating the robot by a laser with alternating or fixed polarization synergistically results in basic movement (backward and forward) and turning (including left-, right-, and U-turn), respectively. A complex walk along predesigned pathways can be potentially programmed by combining the movement and turning modes of the robots. This strategy provides an alternative driving mechanism for preparing functional soft robots, thus breaking through the limitations in the existing systems in terms of light sources and actuation manners.
光热致动器因其能够将光能转化为机械变形和运动而受到越来越多的关注。这项工作报道了一种独立的、多向光热机器人，它可以通过调制激光偏振和开关来沿着预先设计的路径行走。采用一种非常规的模板方法合成了磁性-等离子体混合Fe₃O₄/Ag纳米棒。耦合的磁各向异性和等离子体各向异性使得通过简单地施加磁场就可以控制棒的取向、等离子体激发和光热转换。一旦通过磁场辅助光刻将纳米棒以所需的取向固定在双压电晶片致动器中，就可以通过切换激光偏振来控制致动器的弯曲。通过将棒的取向与其两条腿的交替致动相结合，创建了一个双足机器人。用具有交替或固定偏振的激光照射机器人，分别协同地导致基本运动（向后和向前）和转向（包括左、右和U形转弯）。通过组合机器人的运动和转向模式，可以潜在地对沿着预先设计路径的复杂行走进行编程。这种策略为制备功能性软机器人提供了一种替代驱动机制，从而突破了现有系统在光源和致动方式方面的限制。
