Paving the way toward reactive self-assembly-induced colloidal covalent organic frameworks: Elaboration of macromolecular growth-blocking agents

Abstract

Herein, we develop an original strategy to limit rapid precipitation in solution of Covalent Organic Frameworks (COFs), permitting both the control of their morphology and processing. The enhance COF dispersibility can be implemented and controlled by growth-blocking macromolecular agent concepts. This macromolecular agent limits the growth of COFs and stabilized the COF in a colloidal shape. We propose the synthesis of a hydrophilic end-chain functional Poly(DiMethylAmino)Ethyl MethAcrylate (PDMAEMA) as a macromolecular growth-blocking agent, designed to stabilize imine-COF in aqueous media. Its reactivity with a tri-functional imine-COF blockbuilder (Tpa) is investigated via two different strategies: grafting from and grafting to. This concept is followed by several characterization techniques in solution and in solid states. Depending on the PDMAEMA/Tpa ratios and the grafting strategy, several populations, from mono- to tri-functionalized Tpa are synthesized, and the colloids size and morphology can be tuned. A concomitant DFT calculations provide a better understanding of the self-assembly of the building blocks, shedding the light on the Tpa stacking effects. This study finally provides a first step toward the synthesis of electrostatically/sterically stabilized colloidal COF in water media, for photo hydrogen evolution reaction.