Institute of Advanced Synthesis, and School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 211816 Nanjing, China.
J Am Chem Soc. 2020 Jun 17;142(24):10629-10633. doi: 10.1021/jacs.0c03445. Epub 2020 Jun 8.
Braiding is a common skill in daily life but rare at the nanoscale. Most of the current nanohelices are directly grown or assembled without involving mechanical interactions, and they are thus distinctively different from ropes in terms of functions and mechanisms. Here, by coaxially twisting multiple ultrathin Au nanowires, nanoropes are synthesized with elegant helical patterns that are consistent with the macroscopic equivalents. The strain relaxation of lattice transformation causes the nanowires to pursue the maximum degree of twisting, while the mutual packing interactions in a bundle prevent sideways emergence of U-turns. The consistent chirality of the seemingly independent strands can only arise when a first twisting strand causes morphological deformation in its neighbors, which induces the collective uni-directional twisting. The spontaneous braiding and the "remote" control of the nanowires involve mechanical interactions and possibly energy transmission, thus opening doors to chiral assembly and future smart nanodevices.
编辫是日常生活中的常见技能，但在纳米尺度却很少见。目前大多数纳米螺旋体都是直接生长或组装而成，不涉及机械相互作用，因此在功能和机制方面与绳索明显不同。在这里，通过同轴扭转多个超薄 Au 纳米线，合成了具有优雅螺旋图案的纳米绳，这些图案与宏观等效物一致。晶格转变的应变松弛导致纳米线追求最大程度的扭转，而在束中的相互堆积相互作用则阻止了 U 型转弯的侧向出现。当第一个扭转的链在其相邻链中引起形态变形，从而诱导集体单向扭转时，看似独立的链的一致手性才会出现。纳米线的自发编辫和“远程”控制涉及机械相互作用，并且可能涉及能量传输，从而为手性组装和未来的智能纳米器件开辟了道路。
