美国加州大学Xu, Ting团队报道了通过编程熵驱动纳米片生长的功能复合材料。相关研究成果于2023年11月8日发表咋国际知名学术期刊《自然》。

纳米材料必须系统地设计为在技术上可行的。在优化分子间相互作用的驱动下，目前的设计过于僵化，无法插入新的化学官能团，也无法缓解整合过程中的条件差异。尽管对构建块和处理进行了广泛的优化，但获得具有所需特征尺寸和化学性质的纳米结构是困难的。，规划他们从纳米到宏观的增长即便不是不可能，但也仍然具有挑战性。为了解决这些限制，研究人员应该转向熵驱动组件，以获得设计灵活性，就像在高熵合金中所见，并对纳米材料生长进行编程，以在加工过程中使目标特征尺寸与系统的迁移率动态匹配。

该文中，在由嵌段共聚物基超分子、小分子和纳米颗粒组成的三元复合混合物中，按照先微后纳米的生长顺序，研究人员成功地制备了由200多个堆叠的纳米片（125 nm片厚度），其缺陷密度小于0.056 µm⁻²，控制缺陷类型的效率约为98%。与通常的看法相反，聚合物链缠结有利于实现长程制备，加速制造过程（<30 min），并满足推进多层膜技术的特定要求。

该项研究展示了通过自组装的系统工程将实验室纳米科学转化为纳米技术的可行性、必要性和无限机会。按照微-纳米生长顺序制备由嵌段共聚物基超分子、小分子和纳米颗粒混合而成的复合材料表明，可以通过熵驱动组装的方式制造高性能屏蔽材料。

附：英文原文

Title: Functional composites by programming entropy-driven nanosheet growth

Author: Vargo, Emma, Ma, Le, Li, He, Zhang, Qingteng, Kwon, Junpyo, Evans, Katherine M., Tang, Xiaochen, Tovmasyan, Victoria L., Jan, Jasmine, Arias, Ana C., Destaillats, Hugo, Kuzmenko, Ivan, Ilavsky, Jan, Chen, Wei-Ren, Heller, William, Ritchie, Robert O., Liu, Yi, Xu, Ting

Issue&Volume: 2023-11-08

Abstract: Nanomaterials must be systematically designed to be technologically viable1–5. Driven by optimizing intermolecular interactions, current designs are too rigid to plug in new chemical functionalities and cannot mitigate condition differences during integration6,7. Despite extensive optimization of building blocks and treatments, accessing nanostructures with the required feature sizes and chemistries is difficult. Programming their growth across the nano-to-macro hierarchy also remains challenging, if not impossible8–13. To address these limitations, we should shift to entropy-driven assemblies to gain design flexibility, as seen in high-entropy alloys, and program nanomaterial growth to kinetically match target feature sizes to the mobility of the system during processing14–17. Here, following a micro-then-nano growth sequence in ternary composite blends composed of block-copolymer-based supramolecules, small molecules and nanoparticles, we successfully fabricate high-performance barrier materials composed of more than 200 stacked nanosheets (125 nm sheet thickness) with a defect density less than 0.056 µm−2 and about 98% efficiency in controlling the defect type. Contrary to common perception, polymer-chain entanglements are advantageous to realize long-range order, accelerate the fabrication process (&lt;30 min) and satisfy specific requirements to advance multilayered film technology3,4,18. This study showcases the feasibility, necessity and unlimited opportunities to transform laboratory nanoscience into nanotechnology through systems engineering of self-assembly. Following a micro-then-nano growth sequence to fabricate composites that are blends of block-copolymer-based supramolecules, small molecules and nanoparticles shows that high-performance barrier materials can be manufactured by means of entropy-driven assembly.

DOI: 10.1038/s41586-023-06660-x

Source: https://www.nature.com/articles/s41586-023-06660-x