Li Jianjie, He Xiaoli, Jiang Huaide, Xing Yi, Fu Bi, Hu Chengzhi
Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2022 Aug 10;14(31):36027-36037. doi: 10.1021/acsami.2c08464. Epub 2022 Aug 2.
Advances in the versatile design and synthesis of nanomaterials have imparted diverse functionalities to Janus micromotors as autonomous vehicles. However, a significant challenge remains in maneuvering Janus micromotors by following desired trajectories for on-demand motility and intelligent control due to the inherent rotational Brownian motion. Here, we present the enhanced and robust directional propulsion of light-activated FeO@TiO/Pt Janus micromotors by magnetic spinning and the Magnus effect. Once exposed to a low-intensity rotating magnetic field, the micromotors become physically actuated, and their rotational Brownian diffusion is quenched by the magnetic rotation. Photocatalytic propulsion can be triggered by unidirectional irradiation based on a self-electrophoretic mechanism. Thus, a transverse Magnus force can be generated due to the rotational motion and ballistic motion (photocatalytic propulsion) of the micromotors. Both the self-electrophoretic propulsion and the Magnus force are periodically changed due to the magnetic rotation, which results in an overall directed motion moving toward a trajectory with a deflection angle from the direction of incident light with enhanced speed, maneuverability, and steering robustness. Our study illustrates the admirable directional motion capabilities of light-driven Janus micromotors based on magnetic spinning and the Magnus effect, which unfolds a new paradigm for addressing the limitations of directionality control in the current asymmetric micromotors.
纳米材料通用设计与合成方面的进展赋予了Janus微电机作为自主载体的多种功能。然而，由于固有的旋转布朗运动，要让Janus微电机按照所需轨迹进行按需运动和智能控制以实现操纵，仍然存在重大挑战。在此，我们展示了通过磁旋转和马格努斯效应实现光激活的FeO@TiO/Pt Janus微电机增强且稳健的定向推进。一旦暴露于低强度旋转磁场中，微电机就会被物理驱动，其旋转布朗扩散会被磁旋转淬灭。基于自电泳机制，单向照射可触发光催化推进。因此，由于微电机的旋转运动和弹道运动（光催化推进），可以产生横向马格努斯力。由于磁旋转，自电泳推进和马格努斯力都会周期性变化，这导致整体定向运动朝着与入射光方向有偏转角的轨迹移动，速度、机动性和转向稳健性都有所增强。我们的研究展示了基于磁旋转和马格努斯效应的光驱动Janus微电机令人钦佩的定向运动能力，为解决当前不对称微电机方向性控制的局限性开辟了新的范例。
