Converting planar polymer films into sophisticated 3D structures with a facile and effective method is highly challenging yet desirable for device applications in the real world. Dynamic covalent polymer networks enable permanent shape transformations from 2D sheets to 3D structures, but either sophisticated molecular design or a complex fabrication method is required. Here, we report a shape memory polymer cross-linked by ester bonds, which can be activated upon heating after photoexposure to release the catalyst for the transesterification. The region that is activated via the bond exchange can be patterned due to the spatial-temporal selectivity of the photoexposure. Accordingly, the material presents a localized heterogeneity in stress relaxation upon stretching. The exposed and the unexposed regions show respectively plastic deformation and elastic recovery after removal of the external force, which finally make the 2D sheet transform into a 3D structure. The decoupling of the activated region (photoexposure) and activated condition (heating) enables facile chemical design and fabrication for 2D-to-3D shape morphing.

中文翻译：

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Thermadapt 形状记忆聚合物可实现空间调节的可塑性

用一种简单有效的方法将平面聚合物薄膜转换为复杂的 3D 结构是极具挑战性的，但对于现实世界中的设备应用来说是理想的。动态共价聚合物网络能够实现从 2D 片材到 3D 结构的永久形状转换，但需要复杂的分子设计或复杂的制造方法。在这里，我们报道了一种通过酯键交联的形状记忆聚合物，它可以在曝光后加热时被激活，从而释放出酯交换催化剂。由于曝光的时空选择性，通过键交换激活的区域可以被图案化。因此，该材料在拉伸时呈现出局部的应力松弛不均匀性。暴露区域和未暴露区域在去除外力后分别表现出塑性变形和弹性恢复，最终使2D片材转变为3D结构。激活区域（曝光）和激活条件（加热）的去耦使得能够轻松进行 2D 到 3D 形状变形的化学设计和制造。