Ultrathin 2D Covalent Organic Framework Film Fabricated via Langmuir-Blodgett Method with a “Two-in-One” Type Monomer

I n recent years, covalent organic frameworks(COFs) are evolving as a novel kind of porous materials for catalysis and molecular separation, gas adsorption, etc. Various functional building blocks have been explored to tune the pore channels, including the pore size and structures. In this article, a new terphenyl(TP) based COF(TP-COF) was developed via a “two-in-one” strategy by using a symmetric A 2 B 2 monomer, i.e. , 4,4″-diamino-2′,5′-diformyl-1,1′:4′,1″-terphenyl(DADFTP). The pore size of TP-COF was only 0.99 nm by shortening the arm length of the DADFTP monomer. Freestanding, continuous and ultrathin COF films could be facilely prepared at the air-liquid interface through the modified Langmuir-Blodgett(LB) method. TP-COF films exhibited high rejection of over 90% for dyes removal.