Mixtures of filaments and molecular motors form active materials with diverse dynamical behaviors that vary based on their constituents’ molecular properties. To develop a multiscale of these materials, we map the nonequilibrium phase diagram of microtubules and tip-accumulating kinesin-4 molecular motors. We find that kinesin-4 can drive either global contractions or turbulentlike extensile dynamics, depending on the concentrations of both microtubules and a bundling agent. We also observe a range of spatially heterogeneous nonequilibrium phases, including finite-sized radial asters, 1D wormlike chains, extended 2D bilayers, and system-spanning 3D active foams. Finally, we describe intricate kinetic pathways that yield microphase separated structures and arise from the inherent frustration between the orientational order of filamentous microtubules and the positional order of tip-accumulating molecular motors. Our work reveals a range of novel active states. It also shows that the form of active stresses is not solely dictated by the properties of individual motors and filaments, but is also contingent on the constituent concentrations and spatial arrangement of motors on the filaments.

中文翻译：

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微管和尖端累积分子马达混合物中的主动微相分离

细丝和分子马达的混合物形成具有多种动力学行为的活性材料，这些行为根据其成分的分子特性而变化。为了开发这些材料的多尺度，我们绘制了微管和尖端累积驱动蛋白 4 分子马达的非平衡相图。我们发现，kinesin-4 可以驱动整体收缩或湍流状伸展动力学，具体取决于微管和成束剂的浓度。我们还观察到一系列空间异质非平衡相，包括有限尺寸的径向紫苑、一维蠕虫状链、扩展的二维双层和跨系统的 3D 活性泡沫。最后，我们描述了产生微相分离结构的复杂动力学路径，这些路径是由丝状微管的取向顺序和尖端累积分子马达的位置顺序之间固有的挫败引起的。我们的工作揭示了一系列新颖的活性状态。它还表明，主动应力的形式不仅取决于各个电机和灯丝的特性，而且还取决于灯丝上电机的成分浓度和空间排列。