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.

中文翻译：

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边界可以引导活动的Janus球体。

自主自我推进技术的出现促使人们开始研究制造胶体机器，该机器可以以运输的形式提供机械功，并具有其他功能，例如感应和清洁。在过去的十年中，尽管在产生自推进力的各种机制方面已取得了很大进展，但迄今为止，操纵自推进胶体装置的能力受到了更大的限制。增大此类电动机的冲击力的一个关键障碍是使电动机的运动与布朗旋转方向相反，而布朗旋转会使粒子方向随机化。在这种情况下，在此我们报告当靠近固体表面运动时，特定类别的催化电机的定向运动。这是通过将布朗布朗旋转约束在旋转井中（不是由平衡引起的）进行主动淬火来实现的，但受流体动力影响。我们演示了如何结合使用这些几何约束来引导这些活性胶体沿着任意轨迹运动。