Yuan Hongye, Liu Guoliang, Qiao Zhiwei, Li Nanxi, Buenconsejo Pio John S, Xi Shibo, Karmakar Avishek, Li Mengsha, Cai Hong, Pennycook Stephen John, Zhao Dan
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.
State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China.
Adv Mater. 2021 Jul;33(29):e2101257. doi: 10.1002/adma.202101257. Epub 2021 May 31.
Metal-organic frameworks (MOFs) intrinsically lack fluidity and thus solution processability. Direct synthesis of MOFs exhibiting solution processability like polymers remains challenging but highly sought-after for multitudinous applications. Herein, a one-pot, surfactant-free, and scalable synthesis of highly stable MOF suspensions composed of exceptionally large (average area > 15 000 µm ) NUS-8 nanosheets with variable functionalities and excellent solution processability is presented. This is achieved by adding capping molecules during the synthesis, and by judicious controls of precursor concentration and MOF nanosheet-solvent interactions. The resulting 2D NUS-8 nanosheets with variable functionalities exhibit excellent solution processability. As such, relevant monoliths, aero- and xerogels, and large-area textured films with a great homogeneity, controllable thickness, and appreciable mechanical properties can be facilely fabricated. Additionally, from both the molecular- and chip-level it is demonstrated that capacitive sensors integrated with NUS-8 films functionalized with different terminal groups exhibit distinguishable sensing behaviors toward acetone due to their disparate host-guest interactions. It is envisioned that this simple approach will greatly facilitate the integration of MOFs in miniaturized electronic devices and benefit their mass production.
金属有机框架材料(MOFs)本质上缺乏流动性,因此缺乏溶液可加工性。像聚合物一样具有溶液可加工性的MOFs的直接合成仍然具有挑战性,但在众多应用中备受追捧。在此,我们提出了一种一锅法、无表面活性剂且可扩展的合成方法,用于制备由尺寸特别大(平均面积>15000 µm²)、具有可变功能且溶液可加工性优异的NUS-8纳米片组成的高度稳定的MOF悬浮液。这是通过在合成过程中添加封端分子,并明智地控制前驱体浓度和MOF纳米片与溶剂的相互作用来实现的。由此得到的具有可变功能的二维NUS-8纳米片表现出优异的溶液可加工性。因此,可以轻松制备出具有良好均匀性、可控厚度和可观机械性能的相关整体材料、气凝胶和干凝胶以及大面积纹理化薄膜。此外,从分子和芯片层面都证明,与用不同端基功能化的NUS-8薄膜集成的电容式传感器,由于其不同的主客体相互作用,对丙酮表现出可区分的传感行为。可以设想,这种简单的方法将极大地促进MOFs在小型化电子设备中的集成,并有利于其大规模生产。