Resumen de Processing of Imine-Based Covalent Organic Frameworks
Covalent organic frameworks (COFs) are a fairly novel type of porous materials characterised by being made of light elements joined by covalent bonds forming ordered and periodic networks. They have shown potential in a range of applications comprising from water purification to solar energy collection. However, its processability is underdeveloped and hinders its incorporation in functional devices. Thus, in this thesis, several approaches to process imine-linked COFs that have been developed during the last four years are described.
The first introductory chapter is intended to provide a general overview of COFs, explaining its design, the requisites they must fulfil, their chemistry and their properties and applications; in addition to a more comprehensive list of the processing methodologies that have been reported to date.
In Chapter 2, the first reported procedure for the room temperature synthesis of imine-based COFs is described. Moreover, taking advantage of this new possibility, patterns of COF are created on different substrates using inkjet printing and soft lithography.
Chapter 3 describes the synthesis of COFs in microfluidic systems, which results in the formation of crystalline materials with an unprecedented fibrous morphology in a few seconds.
In Chapter 4, the procedures developed in the two previous chapters are employed to prepare COFs loaded with different molecules enhancing their ionic conductivity. It is found that the addition of a small amount of acetic acid when pressing the powder to shape it allows the formation of continuous COF films and that this processing methodology has a critical effect on the performance of the material as a membrane in fuel cells.
Finally, the last chapter describes the formation of monodisperse COF spheres in a two-step amorphous sphere formation/recrystallisation process that also enables the encapsulation of functional metal and metal oxide nanoparticles which are demonstrated to preserve their properties and be accessible due to the porous nature of the surrounding COF.
