Skeletal muscle provides inspiration on how to achieve reversible, macroscopic, anisotropic motion in soft materials. Here we report on the bottom-up design of macroscopic tubes that exhibit anisotropic actuation driven by a thermal stimulus. The tube is built from a hydrogel in which extremely long supramolecular nanofibers are aligned using weak shear forces, followed by radial growth of thermoresponsive polymers from their surfaces. The hierarchically ordered tube exhibits reversible anisotropic actuation with changes in temperature, with much greater contraction perpendicular to the direction of nanofiber alignment. We identify two critical factors for the anisotropic actuation, macroscopic alignment of the supramolecular scaffold and its covalent bonding to polymer chains. Using finite element analysis and molecular calculations, we conclude polymer chain confinement and mechanical reinforcement by rigid supramolecular nanofibers are responsible for the anisotropic actuation. The work reported suggests strategies to create soft active matter with molecularly encoded capacity to perform complex tasks.

中文翻译：

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共价超分子杂化聚合物，作为肌肉启发的各向异性促动器。

骨骼肌为如何在软质材料中实现可逆的宏观各向异性运动提供了灵感。在这里，我们报告了由热刺激驱动的具有各向异性驱动作用的宏观管的自下而上的设计。该管由水凝胶制成，其中极长的超分子纳米纤维使用弱剪切力排列，然后从其表面径向生长热敏性聚合物。分层排列的管在温度变化时表现出可逆的各向异性驱动，垂直于纳米纤维排列方向的收缩更大。我们确定了各向异性驱动的两个关键因素，超分子支架的宏观排列及其与聚合物链的共价键合。使用有限元分析和分子计算，我们得出结论，刚性超分子纳米纤维对聚合物链的限制和机械增强是各向异性驱动的原因。报告的工作提出了创建具有分子编码能力的软活性物质以执行复杂任务的策略。