Li Yang, Zhang Meicheng, Guo Xinghua, Wen Rui, Li Xing, Li Xiaofeng, Li Shoujian, Ma Lijian
College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics & Technology, Ministry of Education, No. 29 Wangjiang Road, Chengdu, 610064, P. R. China.
Nanoscale Horiz. 2018 Mar 1;3(2):205-212. doi: 10.1039/c7nh00172j. Epub 2018 Jan 24.
Stronger covalent bonds between monomers, relatively more complex growth processes (polymerization, crystallization, assembly, etc.) and π-π stacking interactions between adjacent layers make it extremely difficult to obtain highly ordered crystalline 2D covalent organic framework (COF) nanosheets. So more effective solutions have to be developed to push the methods reported so far beyond their inherent limitations. Herein, we report the first example of growing high-quality 2D COF nanosheets (NS-COF) at the interface of two miscible organic solvents. The novel approach, which is named as a buffering interlayer interface (BII) method, can be achieved by simply adding a low-density solvent interlayer, as a buffer layer, between the two miscible main solvents based on the self-propelled directed motion of the interface driven by the density differences among the solvents involved. The as-synthesized NS-COF exhibits a super-large size and a relatively regular shape with a smooth surface, which have not been observed before. The proposed strategy offers a facile and effective approach for growing well-structured 2D COF nanosheets and also other kinds of nanosheets.
单体之间更强的共价键、相对更复杂的生长过程（聚合、结晶、组装等）以及相邻层之间的π-π堆积相互作用使得获得高度有序的结晶二维共价有机框架（COF）纳米片极其困难。因此，必须开发更有效的解决方案，以突破目前报道方法的固有局限性。在此，我们报道了在两种互溶有机溶剂的界面上生长高质量二维COF纳米片（NS-COF）的首个实例。这种新方法被命名为缓冲夹层界面（BII）法，通过基于所涉及溶剂之间的密度差异驱动的界面自推进定向运动，在两种互溶的主要溶剂之间简单地添加一个低密度溶剂夹层作为缓冲层即可实现。所合成的NS-COF展现出超大尺寸和相对规则的形状，且表面光滑，这些都是前所未有的。所提出的策略为生长结构良好的二维COF纳米片以及其他种类的纳米片提供了一种简便有效的方法。
