Artificial model swimmers offer a platform to explore the physical principles enabling biological complexity, for example, multigait motility: a strategy employed by many biomicroswimmers to explore and react to changes in their environment. Here, we report bimodal motility in autophoretic droplet swimmers, driven by characteristic interfacial flow patterns for each propulsive mode. We demonstrate a dynamical transition from quasiballistic to bimodal chaotic propulsion by controlling the viscosity of the environment. To elucidate the physical mechanism of this transition, we simultaneously visualize hydrodynamic and chemical fields and interpret these observations by quantitative comparison to established advection-diffusion models. We show that, with increasing viscosity, higher hydrodynamic modes become excitable and the droplet recurrently switches between two dominant modes due to interactions with the self-generated chemical gradients. This type of self-interaction promotes self-avoiding walks mimicking examples of efficient spatial exploration strategies observed in nature.

中文翻译：

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主动液滴中双峰动力的出现

人工模型游泳者提供了一个平台，探索促进生物复杂性的物理原理，例如，多步态运动：许多生物微泳者采用的一种策略，以探索其环境变化并对之做出反应。在这里，我们报道了在自动泳飞沫游泳者中的双峰运动，这是由每个推进模式的特征性界面流动模式所驱动的。我们通过控制环境的粘性来证明从准弹道到双峰混沌推进的动态过渡。为了阐明这种转变的物理机制，我们同时可视化了流体动力学和化学领域，并通过与建立的对流扩散模型进行定量比较来解释这些观测结果。我们表明，随着粘度的增加，更高的流体动力学模式变得可激发，并且由于与自生化学梯度的相互作用，液滴在两个主导模式之间循环切换。这种类型的自我互动促进了自我规避的散步，模仿了自然界中观察到的有效空间探索策略的实例。