Chemotactic interactions are ubiquitous in nature and can lead to non-reciprocal and complex emergent behaviour in multibody systems. However, developing synthetic, inanimate embodiments of a chemomechanical framework to generate non-reciprocal interactions of tunable strength and directionality has been challenging. Here we show how chemotactic signalling between microscale oil droplets of different chemistries in micellar surfactant solutions can result in predator–prey-like non-reciprocal chasing interactions. The interactions and dynamic self-organization result from the net directional, micelle-mediated transport of oil between emulsion droplets of differing composition and are powered by the free energy of mixing. We systematically elucidated chemical design rules to tune the interactions between droplets by varying the oil and surfactant chemical structure and concentration. Through the integration of experiment and simulation, we also investigated the active behaviour and dynamic reorganization of multidroplet clusters. Our findings demonstrate how chemically minimal systems can be designed with controllable, non-reciprocal chemotactic interactions to generate emergent self-organization and collective behaviours reminiscent of biological systems.

趋化相互作用在自然界中无处不在，可导致多体系统中的非互惠和复杂的紧急行为。然而，开发化学机械框架的合成的、无生命的实施例以产生可调强度和方向性的非互易相互作用一直具有挑战性。在这里，我们展示了胶束表面活性剂溶液中不同化学成分的微尺度油滴之间的趋化信号如何导致捕食者-猎物类非互易追逐相互作用。相互作用和动态自组织是由油在不同成分的乳液液滴之间的净定向、胶束介导的传输产生的，并由混合的自由能提供动力。我们系统地阐明了化学设计规则，通过改变油和表面活性剂的化学结构和浓度来调整液滴之间的相互作用。通过实验和模拟相结合，我们还研究了多液滴簇的主动行为和动态重组。我们的研究结果证明了如何通过可控的、非互易的趋化相互作用来设计化学最小系统，以产生让人联想到生物系统的紧急自组织和集体行为。