Debata Srikanta, Panda Suvendu Kumar, Trivedi Satyaprakash, Uspal William, Singh Dhruv Pratap
Department of Physics, IIT Bhilai, Kutelabhata, Durg, Chhattisgarh, 491001, India.
Department of Mechanical Engineering, University of Hawai'i at Mānoa, 2540 Dole Street, Holmes Hall 302, Honolulu, HI 96822, USA.
Nanoscale. 2023 Nov 9;15(43):17534-17543. doi: 10.1039/d3nr03775d.
Micromotors have emerged as promising devices for a wide range of applications , microfluidics, lab-on-a-chip devices, active matter, environmental monitoring, . The control over the activity of micromotors with the ability to exhibit multimode swimming is one of the most desirable features for many of the applications. Here, we demonstrate a rod-shaped light-driven micromotor whose activity and swimming behavior can easily be controlled. The rod-shaped micromotors are fabricated through the dynamic shadowing growth (DSG) technique, where a 2 μm long arm of titanium dioxide (TiO) is grown over spherical silica (SiO) particles (1 μm diameter). Under low-intensity UV light exposure, the micromotors exhibit self-propulsion in an aqueous peroxide medium. When activated, the swimming behavior of micromotors greatly depends on the pH of the medium. The swimming direction, , forward or backward movement, as well as swimming modes like translational or rotational motion, can be controlled by changing the pH values. The observed dynamics has been rationalized using a theoretical model incorporating chemical activity, hydrodynamic flow, and the effect of gravity for a rod-shaped active particle near a planar wall. The pH-dependent translational and rotational dynamics of micromotors provide a versatile platform for achieving controlled and responsive behaviors. Continued research and development in this area hold great promise for advancing micromotors and enabling novel applications in microfluidics, micromachining, environmental sciences, and biomedicine.
微电机已成为适用于广泛应用的有前景的设备，如微流体、芯片实验室设备、活性物质、环境监测等。能够展示多模式游动的微电机的活性控制是许多应用中最理想的特性之一。在此，我们展示了一种棒状光驱动微电机，其活性和游动行为能够轻松得到控制。棒状微电机是通过动态阴影生长（DSG）技术制造的，在直径为1μm的球形二氧化硅（SiO）颗粒上生长出一条2μm长的二氧化钛（TiO）臂。在低强度紫外线照射下，微电机在过氧化物水溶液介质中表现出自我推进能力。激活后，微电机的游动行为在很大程度上取决于介质的pH值。通过改变pH值，可以控制游动方向，即向前或向后移动，以及平移或旋转运动等游动模式。利用一个理论模型对观察到的动力学进行了合理化解释，该模型结合了化学活性、流体动力流以及平面壁附近棒状活性粒子的重力效应。微电机的pH值依赖的平移和旋转动力学为实现可控和响应性行为提供了一个通用平台。该领域的持续研发对于推进微电机以及在微流体、微加工、环境科学和生物医学中实现新应用具有巨大潜力。
