Generalized Model for Inhibitor-Modulated 2D Polymer Growth to Understand the Controlled Synthesis of Covalent Organic Frameworks

Paliwal, S and Li, W and Liu, P and Govind Rajan, A (2024) Generalized Model for Inhibitor-Modulated 2D Polymer Growth to Understand the Controlled Synthesis of Covalent Organic Frameworks. In: JACS Au .

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Abstract

Two-dimensional (2D) polymers, also known as 2D covalent organic frameworks (COFs), are increasingly finding use in applications such as membrane separations, catalysis, and energy conversion. Current research is focused on the development of new synthesis routes for COFs and obtaining a mechanistic understanding of the growth process to control it in a better manner. In this regard, synthesis methods such as reversible polycondensation termination use monofunctional inhibitor species to achieve a controlled growth rate for COFs. However, so far, the role of the inhibitors in modulating the kinetics of COF growth is inadequately understood. In this work, inspired by the Mayo-Lewis framework, we develop a generalized kinetic model to describe the synthesis of a 2D COF monolayer. Our model involves six parameters corresponding to the rate constants of attachment and detachment of monomer and inhibitor species, as well as enhancement factors that quantify the effect of the local coordination environment of the attaching/detaching species on the reaction kinetics. We measure the inhibitor concentration-dependent growth kinetics of the COF experimentally and fit our model to experimental yield data, with the same parameters working across multiple inhibitor concentrations. As the growth process is inherently stochastic, we use this knowledge to develop a comprehensive kinetic Monte Carlo (KMC) simulation of 2D COF synthesis, demonstrating that scaled rate constants are required in the inherently local KMC simulations rather than those obtained from the global kinetic model. The KMC simulations point to an inverse flake size-inhibitor concentration relationship, in agreement with experiments, indicating that flake sizes could be precisely regulated by changing the inhibitor concentrations. Overall, our work promises to improve the understanding of 2D COF synthesis and will help in controlling the growth process to obtain the desired flake size distribution and product morphology. © 2024 The Authors. Published by American Chemical Society.

Item Type:	Journal Article
Publication:	JACS Au
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to authors.
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	21 Aug 2024 11:50
Last Modified:	21 Aug 2024 11:50
URI:	http://eprints.iisc.ac.in/id/eprint/85489

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