In nature, organisms control their deformation and locomotion through multi-functional synergy in response to environmental changes. Nowadays, most synthetic biomaterial systems are capable of realizing single-mode actuation movement under external triggers through biomimetic simulation, while complicated and continuous locomotion in artificial materials with multi-dimensional responsiveness remains to be explored. Here we report an anisotropic melem-formaldehyde polymer that is self-assembled from a one-dimensional (1D) chain into a two-dimensional (2D) film. The stimuli-responsive polymer film shows anisotropic responses in both radial and axial directions on contacting with different solvents (liquid or vapor) in a single material. Complex multi-dimensional motion patterns can be actuated and reversibly controlled by virtue of different interactions within the 1D line and 2D film as well as the gradients along the thickness direction. The developed architecture with tunable and programmable anisotropy is potentially applicable in soft material actuators that can operate in various environments.

中文翻译：

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甲基甲醛聚合物的刺激响应各向异性致动†

在自然界中，有机体通过响应环境变化的多功能协同作用来控制其变形和运动。如今，大多数合成生物材料系统都能够通过仿生模拟在外部触发条件下实现单模致动运动，而具有多维响应性的人造材料中复杂而连续的运动仍有待探索。在这里，我们报告了一种各向异性的蜜胺-甲醛聚合物，它从一维（1D）链自动组装成二维（2D）膜。与单一材料中的不同溶剂（液体或蒸气）接触时，刺激响应性聚合物膜在径向和轴向上均显示各向异性响应。复杂的多维运动模式可以通过1D线和2D膜内的不同交互作用以及沿厚度方向的梯度进行激活和可逆控制。具有可调和可编程各向异性的已开发体系结构可能适用于可在各种环境下运行的软质材料执行器。