Self-assembly of aramid amphiphiles into ultra-stable nanoribbons and aligned nanoribbon threads
Self-assembly of aramid amphiphiles into ultra-stable nanoribbons and aligned nanoribbon threads
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DOI：
10.1038/s41565-020-00840-w
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发表时间：
2021-01-18
影响因子：
38.3
通讯作者：
Ortony, Julia H.
中科院分区：
文献类型：
--
作者：
Christoff-Tempesta, Ty;Cho, Yukio;Ortony, Julia H.
小分子自组装是一种生产高表面积纳米结构的既定途径，具有易于定制的化学和精确的分子组织。然而，这些结构是脆弱的，表现出分子交换，迁移和再结晶-在其他动态不稳定性-并且在干燥时易于解离。在这里，我们展示了一个小分子平台，芳族聚酰胺两亲物，克服了这些动态不稳定性，将凯夫拉启发域的分子结构。芳族聚酰胺两亲物之间强的各向异性相互作用抑制分子交换，并在水中引发自发自组装，形成长度高达20微米的纳米带。单个纳米带具有1.7GPa的杨氏模量和1.9GPa的拉伸强度。我们利用这种稳定性，将小分子自组装扩展到溶剂化环境之外的分级有序的宏观材料。通过水剪切对齐过程，我们将芳族聚酰胺两亲物纳米带组织成任意长的柔性线，干燥时可支撑其重量的200倍。干线的拉伸测试提供了杨氏模量（在类似于400和600 MPa之间）和伸长率（在类似于0.6和1.1%之间）的基准，其取决于对抗化学。这种自下而上的宏观材料方法可以使自组装纳米材料在历史上无法实现的固态应用受益。
Small-molecule self-assembly is an established route for producing high-surface-area nanostructures with readily customizable chemistries and precise molecular organization. However, these structures are fragile, exhibiting molecular exchange, migration and rearrangement-among other dynamic instabilities-and are prone to dissociation upon drying. Here we show a small-molecule platform, the aramid amphiphile, that overcomes these dynamic instabilities by incorporating a Kevlar-inspired domain into the molecular structure. Strong, anisotropic interactions between aramid amphiphiles suppress molecular exchange and elicit spontaneous self-assembly in water to form nanoribbons with lengths of up to 20 micrometres. Individual nanoribbons have a Young's modulus of 1.7 GPa and tensile strength of 1.9 GPa. We exploit this stability to extend small-molecule self-assembly to hierarchically ordered macroscopic materials outside of solvated environments. Through an aqueous shear alignment process, we organize aramid amphiphile nanoribbons into arbitrarily long, flexible threads that support 200 times their weight when dried. Tensile tests of the dry threads provide a benchmark for Young's moduli (between similar to 400 and 600 MPa) and extensibilities (between similar to 0.6 and 1.1%) that depend on the counterion chemistry. This bottom-up approach to macroscopic materials could benefit solid-state applications historically inaccessible by self-assembled nanomaterials.