Products Cited in Publications Worldwide Structural Control of Covalent Organic Frameworks on the Nanoscale

Structural Control of Covalent Organic Frameworks on the Nanoscale

Li, Rebecca Lynn

Abstract

Covalent organic frameworks (COFs) are a class of two-or three-dimensional polymers with emergent properties such as crystallinity, high surface area, and modularity. Over the last decade, the COF literature has pushed the limits of possible COF structures and their corresponding potential applications. Here we describe the different strategies to control COF structure from the nanoscale to the macroscale and the challenges that needs to be addressed to move the field forward (Chapter 1). While methods to access COFs from two or less monomers are very established, synthesizing COFs from more than two monomers is still an underexplored strategy to increase the structural and functional complexity of COFs. We synthesized the first COF solid solutions from a mixture of differently sized dialdehyde monomers which is a new COF structure type where both monomers are homogeneously distributed throughout a single phase crystalline lattice at variable compositions (Chapter 2). Due to the potential of tuning COF properties via composition with this strategy, we expanded the scope of monomers that can be mixed by investigating the compositional phase space of a mixture of tetrafunctional amine monomers that form parent COFs of different topologies (Chapter 3). As available COF monomers have different geometries, we subsequently examined the structures synthesized from a mixture of geometrically incompatible monomers (Chapter 4). Lastly, we synthesized COFs as solution processable nanoparticles unlike the insoluble COF powders synthesized from typical methods and demonstrated particle size control (Chapter 5). This work will guide future multiple component COF synthesis to target more sophisticated functionalities with the insights gained here and motivate potential applications to leverage the solution stable nature of COF nanoparticles.

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