Microscopic motility is a property that emerges from systems of interacting molecules. Unraveling the mechanisms underlying such motion requires coupling the chemistry of molecules with physical processes that operate at larger length scales. Here, we show that photoactive micelles composed of molecular switches gate the autonomous motion of oil droplets in water. These micelles switch from large trans-micelles to smaller cis-micelles in response to light, and only the trans-micelles are effective fuel for the motion. Ultimately, it is this light that controls the movement of the droplets via the photochemistry of the molecules composing the micelles used as fuel. Notably, the droplets evolve positive photokinetic movement, and in patchy light environments, they preferentially move toward peripheral areas as a result of the difference in illumination conditions at the periphery. Our findings demonstrate that engineering the interplay between molecular photo-chemistry and microscopic motility allows designing motile systems rationally.

微观运动是相互作用分子系统产生的一种特性。揭示这种运动背后的机制需要将分子的化学与在更大长度尺度上运行的物理过程结合起来。在这里，我们展示了由分子开关组成的光活性胶束控制了水中油滴的自主运动。这些胶束响应光从大的反式胶束转变为较小的顺式胶束，并且只有反式胶束是运动的有效燃料。最终，正是这种光通过构成用作燃料的胶束的分子的光化学来控制液滴的运动。值得注意的是，液滴会发生正光动运动，并且在斑驳的光照环境中，由于外围照明条件的差异，它们优先向外围区域移动。我们的研究结果表明，通过设计分子光化学和微观运动之间的相互作用，可以合理地设计运动系统。