It is well-known that micro- and nanoparticles can move by phoretic effects in response to externally imposed gradients of scalar quantities such as chemical concentration or electric potential. A class of active colloids can propel themselves through aqueous media by generating local gradients of concentration and electrical potential via surface reactions. Phoretic active colloids can be controlled using external stimuli and can mimic collective behaviors exhibited by many biological swimmers. Low–Reynolds number physicochemical hydrodynamics imposes unique challenges and constraints that must be understood for the practical potential of active colloids to be realized. Here, we review the rich physics underlying the operation of phoretic active colloids, describe their interactions and collective behaviors, and discuss promising directions for future research.

中文翻译：

---

泳姿自我推进

众所周知，微米和纳米粒子可以通过泳动效应移动，以响应外部施加的标量梯度，例如化学浓度或电势。一类活性胶体可以通过表面反应产生局部浓度梯度和电势来推动自己穿过水性介质。泳动活性胶体可以使用外部刺激来控制，并且可以模仿许多生物游泳者表现出的集体行为。低雷诺数物理化学流体动力学带来了独特的挑战和限制，必须了解这些挑战和限制，才能实现活性胶体的实际潜力。在这里，我们回顾了泳动活性胶体运作背后的丰富物理学，描述了它们的相互作用和集体行为，