Solution-Processable Metal-Organic Framework Nanosheets with Variable Functionalities

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 mu m(2)) 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.

Automated summary

This study presents a simple and surfactant-free method for synthesizing highly stable MOF suspensions composed of exceptionally large NUS-8 nanosheets, demonstrating excellent solution processability. The resulting NUS-8 nanosheets can be used to fabricate materials with controllable thickness and good mechanical properties, and capacitive sensors integrated with NUS-8 films functionalized with different terminal groups exhibit distinguishable sensing behaviors toward acetone.