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Self-assembly of a layered two-dimensional molecularly woven fabric
Nature ( IF 64.8 ) Pub Date : 2020-12-16 , DOI: 10.1038/s41586-020-3019-9
David P. August , Robert A. W. Dryfe , Sarah J. Haigh , Paige R. C. Kent , David A. Leigh , Jean-François Lemonnier , Zheling Li , Christopher A. Muryn , Leoni I. Palmer , Yiwei Song , George F. S. Whitehead , Robert J. Young

Fabrics-materials consisting of layers of woven fibres-are some of the most important materials in everyday life1. Previous nanoscale weaves2-16 include isotropic crystalline covalent organic frameworks12-14 that feature rigid helical strands interlaced in all three dimensions, rather than the two-dimensional17,18 layers of flexible woven strands that give conventional textiles their characteristic flexibility, thinness, anisotropic strength and porosity. A supramolecular two-dimensional kagome weave15 and a single-layer, surface-supported, interwoven two-dimensional polymer16 have also been reported. The direct, bottom-up assembly of molecular building blocks into linear organic polymer chains woven in two dimensions has been proposed on a number of occasions19-23, but has not previously been achieved. Here we demonstrate that by using an anion and metal ion template, woven molecular 'tiles' can be tessellated into a material consisting of alternating aliphatic and aromatic segmented polymer strands, interwoven within discrete layers. Connections between slowly precipitating pre-woven grids, followed by the removal of the ion template, result in a wholly organic molecular material that forms as stacks and clusters of thin sheets-each sheet up to hundreds of micrometres long and wide but only about four nanometres thick-in which warp and weft single-chain polymer strands remain associated through periodic mechanical entanglements within each sheet. Atomic force microscopy and scanning electron microscopy show clusters and, occasionally, isolated individual sheets that, following demetallation, have slid apart from others with which they were stacked during the tessellation and polymerization process. The layered two-dimensional molecularly woven material has long-range order, is birefringent, is twice as stiff as the constituent linear polymer, and delaminates and tears along well-defined lines in the manner of a macroscopic textile. When incorporated into a polymer-supported membrane, it acts as a net, slowing the passage of large ions while letting smaller ions through.

中文翻译:

层状二维分子机织物的自组装

织物——由多层编织纤维组成的材料——是日常生活中最重要的材料之一。以前的纳米级编织 2-16 包括各向同性结晶共价有机框架 12-14,其特点是刚性螺旋线在所有三个维度上交织,而不是二维 17,18 层柔性编织线,赋予传统纺织品其特有的柔韧性、薄度、各向异性强度和孔隙率。还报道了超分子二维 kagome 编织 15 和单层、表面支撑、交织的二维聚合物 16。已经多次提出将分子构建块直接自下而上组装成二维编织的线性有机聚合物链 19-23,但以前没有实现。在这里,我们证明了通过使用阴离子和金属离子模板,可以将编织分子“瓷砖”镶嵌成由交替的脂肪族和芳香族链段聚合物链组成的材料,它们交织在离散层中。缓慢沉淀的预编织网格之间的连接,然后去除离子模板,形成完全有机的分子材料,形成堆叠和成簇的薄片——每片长和宽可达数百微米,但只有约 4 纳米厚,其中经纱和纬纱单链聚合物股线通过每个片材内的周期性机械缠结保持关联。原子力显微镜和扫描电子显微镜显示出团簇,偶尔会出现孤立的单片,在脱金属后,在镶嵌和聚合过程中,它们与其他堆叠在一起的东西分开了。层状二维分子编织材料具有长程有序、双折射、刚性是组成线性聚合物的两倍,并以宏观纺织品的方式沿着明确定义的线分层和撕裂。当结合到聚合物支撑的膜中时,它充当网,减缓大离子的通过,同时让小离子通过。
更新日期:2020-12-16
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