Synthesis of Thin Film of a Three‐Dimensional Covalent Organic Framework as Anti‐counterfeiting Label

Abstract

Comprehensive Summary Film plays a key role in the sustainable development of our society. Freestanding thin films of two‐dimensional covalent organic frameworks (COFs) have been produced by interface, spin coating, microwave‐assisted synthesis, and screen printing methods and are applied in nanofiltration, molecular separation, photochemical sensing, anion transport, heat conduction, and proton conduction. On the other hand, the synthesis of their three‐dimensional (3D) analogues and subsequent integration in devices remains challenging. Herein, self‐supporting thin films of a three‐dimensional COF with tunable thickness was created by a stearic acid mediated synthesis methodology on water surface at room temperature in air. The film could be transferred onto arbitrary substrate, and when supported on indium tin oxide glass, it exhibited irreversible electrochromism. The optical feature made it act as a one‐time anti‐counterfeiting label in an electrochemical device. This work will inspire the synthesis of thin films of 3D COFs as well as other 3D materials, and boost their property and application exploration.

Postsynthetic Annulation of Three-Dimensional Covalent Organic Frameworks for Boosting CO2 Photoreduction

“…To confirm the formation of imine linkages in NJU-318 and NJU-319Fe, Fourier transform infrared (FTIR) spectra and solid-state nuclear magnetic resonance (ssNMR) spectra were collected (Figures S4–S7). The diminished CO stretching vibration at 1701 cm –1 of the aldehydes and the appearance of characteristic CN stretching vibrations at 1625 cm –1 for NJU-318 and NJU-319Fe corroborated the formation of imine bonds. − Furthermore, the CN peaks (158 ppm for NJU-318 and 159 ppm for NJU-319Fe) in the ssNMR spectra further verified the existence of imine groups in both NJU-318 and NJU-319Fe.…”

Recent Progress of Covalent Organic Frameworks‐Based Materials in Photocatalytic Applications: A Review

“…Recently Dong et al. [ 112 ] proposed the synthesis of a 3D COF film on a water surface at room temperature air using a stearic acid (SA)‐mediated method ( Figure ). The film had a controllable thickness and electrochromic properties.…”

“…Synthesis of Thin Film of a 3D Covalent Organic Framework. Reproduced with permission [112]. Copyright 2022, Wiley-VCH.…”

Three‐Dimensionalsp2Carbon‐LinkedCovalent Organic Frameworks as a Drug Carrier Combined with Fluorescence Imaging

“…Covalent organic frameworks (COFs), [ 1‐6 ] a new class of crystalline porous polymers with large surface areas and high stabilities, have attracted intensive interest in different fields involving gas storage and separation, [ 7‐10 ] catalysis, [ 11‐16 ] organic optoelectronics, [ 17‐21 ] and many others. [ 22‐26 ] To date, most studies are focused on two‐dimensional (2D) architectures with eclipsed AA or staggered AB stacking modes. Three‐dimensional (3D) COFs have recently been considered as promising platforms for a wide range of applications due to unique pore structures, high surface areas and modulated active sites.…”