曼彻斯特大学David A. Leigh等近日取得一项新成果。经过不懈努力，他们通过自组装构建了类似编织物的层状二维分子网格结构。 这一研究成果发表在2020年12月16日出版的国际学术期刊《自然》上。

在本文中，研究人员报道了一种超分子二维Kagome型编织物和一种表面支撑的单层交织二维聚合物材料。此前，由分子模块自下而上直接组装成线性有机高分子链然后编成的二维聚合物已在一些报道中被设计过，但从未真正被成功合成过。

这里，研究人员通过使用一个含阴离子和金属离子的模板，将“分子丝”横竖编成由脂肪链和芳香烃交替排列的聚合物股，然后在分立的层中交织。通过缓慢沉淀的预编格子间形成的连接，以及之后离子模板的移除，研究人员得到了一种以薄层堆积成的全有机分子材料，每一层有数百微米长宽但只有约四纳米厚，其中纵横的聚合物单链通过层中周期性的机械互锁结合在一起。

用原子力显微镜和扫描电子显微镜对其团簇和一些独立的层的分析表明，在去金属化后，原来交织聚合过程中产生的层间堆积已发生滑动。这一层状二维分子编织材料具有长程有序性，具有双折射性，其韧性是构成其的线性聚合物的两倍，并沿着一条明确的线像宏观编织物那样被撕裂。当被整合到一个聚合物支撑的膜中时，该材料就像一张网一样，可以让小离子自由穿透的同时减慢大离子的通过。

据介绍，包含多层编制纤维的纺织物是日常生活中最重要的材料之一。以往的纳米编织物主要包括在三个维度上由刚性螺旋股缠绕的各向同性晶态共价有机框架化合物，但具有类似传统编织物的柔性、超薄、各向异性和多孔纹理的二维层状柔性编织物较少被报道。

附：英文原文

Title: Self-assembly of a layered two-dimensional molecularly woven fabric

Author: David P. August, Robert A. W. Dryfe, Sarah J. Haigh, Paige R. C. Kent, David A. Leigh, Jean-Franois Lemonnier, Zheling Li, Christopher A. Muryn, Leoni I. Palmer, Yiwei Song, George F. S. Whitehead, Robert J. Young

Issue&Volume: 2020-12-16

Abstract: Fabrics—materials consisting of layers of woven fibres—are some of the most important materials in everyday life. Previous nanoscale weaves include isotropic crystalline covalent organic frameworks that feature rigid helical strands interlaced in all three dimensions, rather than the two-dimensional layers of flexible woven strands that give conventional textiles their characteristic flexibility, thinness, anisotropic strength and porosity. A supramolecular two-dimensional kagome weave and a single-layer, surface-supported, interwoven two-dimensional polymer 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 occasions, 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.

DOI: 10.1038/s41586-020-3019-9

Source: https://www.nature.com/articles/s41586-020-3019-9