Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India.
Langmuir. 2022 Mar 1;38(8):2686-2698. doi: 10.1021/acs.langmuir.1c03424. Epub 2022 Feb 15.
Understanding the motion of artificial active swimmers in complex surroundings, such as a dense bath of passive particulate matter, is essential for their successful utilization as cargo (drug) carriers and sensors or for medical imaging, under microscopic domains. In this study, we experimentally investigated the motion of active SiO-Pt Janus particles (JPs) in a two-dimensional bath of smaller silica tracers dispersed with varying areal densities. Our observations indicate that when an active JP undergoes a collision with an isolated tracer, their interaction can have a significant impact on the swimmer's motion. However, the overall impact of tracers on the active JPs' motion (translation and rotation) depends on the frequency of collisions and also on the nature of the collision, which is marked by the time-duration for which the particles maintain contact during the collisions. Further, in the high-density tracer bath, our experiments reveal that the motion of the active JP results in a novel organizational behavior of the tracers on the trailing Pt (depletion of tracers) and the leading SiO (accumulation of tracers) side. In laboratory frame the emergence and the subsequent vanishing of the depletion zone are discussed in detail.
在微观领域中，理解人工主动游泳者在复杂环境中的运动，如密集的被动颗粒物质浴中，对于成功地将其用作货物（药物）载体和传感器或用于医学成像至关重要。在这项研究中，我们通过实验研究了二维浴中较小二氧化硅示踪剂的不同面密度分散的主动 SiO-Pt 詹纳斯粒子 (JP) 的运动。我们的观察表明，当主动 JP 与孤立示踪剂发生碰撞时，它们的相互作用可能对游泳者的运动产生重大影响。然而，示踪剂对主动 JP 运动（平移和旋转）的总体影响取决于碰撞的频率，还取决于碰撞的性质，这由粒子在碰撞过程中保持接触的时间长短来标记。此外，在高密度示踪剂浴中，我们的实验揭示了主动 JP 的运动会导致示踪剂在尾随 Pt（示踪剂耗尽）和领先 SiO（示踪剂积累）侧上产生新颖的组织行为。在实验室框架中，详细讨论了耗散区的出现和随后的消失。
