Boundaries can steer active Janus spheres.
Boundaries can steer active Janus spheres.
复制标题
边界可以引导活跃的Janus球体。
DOI：
10.1038/ncomms9999
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发表时间：
2015-12-02
影响因子：
16.6
通讯作者：
Ebbens SJ
中科院分区：
文献类型：
--
作者：
Das S;Garg A;Campbell AI;Howse J;Sen A;Velegol D;Golestanian R;Ebbens SJ
自主推进的出现推动了人们对胶体机器的研究，这些机器可以以运输的形式提供机械工作，并具有传感和清洁等其他功能。虽然在过去10年里，在产生自推进的各种机制方面取得了很大进展，但到目前为止，引导自推进胶体设备的能力要有限得多。增加这类发动机影响的一个关键障碍是引导它们的运动不受布朗旋转的影响，布朗旋转使粒子方向随机化。在此背景下，我们报告了一类特定类型的催化马达在靠近固体表面移动时的定向运动。这是通过主动猝灭它们的布朗旋转，通过将其限制在旋转势垒中来实现的，这不是由平衡引起的，而是由流体动力学效应引起的。我们演示了如何结合这些几何约束来引导这些活性胶体沿任意轨迹移动。自行式胶体颗粒可以潜在地用于在微尺度上运输货物，但要防止其运动因布朗旋转而随机化是具有挑战性的。在这里，达斯等人。通过坚固的墙来抑制这些旋转，这些墙可以在不需要外部磁场的情况下引导平面内的游泳。
The advent of autonomous self-propulsion has instigated research towards making colloidal machines that can deliver mechanical work in the form of transport, and other functions such as sensing and cleaning. While much progress has been made in the last 10 years on various mechanisms to generate self-propulsion, the ability to steer self-propelled colloidal devices has so far been much more limited. A critical barrier in increasing the impact of such motors is in directing their motion against the Brownian rotation, which randomizes particle orientations. In this context, here we report directed motion of a specific class of catalytic motors when moving in close proximity to solid surfaces. This is achieved through active quenching of their Brownian rotation by constraining it in a rotational well, caused not by equilibrium, but by hydrodynamic effects. We demonstrate how combining these geometric constraints can be utilized to steer these active colloids along arbitrary trajectories. Self-propelled colloidal particles can be potentially used to transport cargoes at the microscale, but it is challenging to prevent randomization of their motion by Brownian rotations. Here, Das et al. quench these rotations by solid walls, which guide in-plane swimming without the need for external fields.