Design of Silicate Hybrid Reticular Networks using Spherosilicate Precursors and Polyfunctional Linkers

Promovendus/a: Jelle Jamoul

Promotor(en): Prof. dr. ir. Johan Martens, De heer Sam Smet

Silicates are a large material family with diverse structures that can be considered built from subunits with discrete numbers of SiO2 monomers. Among the various silicate subunits, silicate cubes show significant potential for developing new silicate hybrid reticular materials due to their nanoscale dimensions, eight-fold symmetry, and ease of functionalization at the corners of the cubes. These subunits can be considered as nodes from where the structural network expands in one, two, or three dimensions, suitable for a wide range of applications like catalysis, adsorption and separation processes, polymer processing, coatings, and sensors.

In this dissertation, two reticular materials featuring silicate cube nodes were synthesized: PolySilicate Porous Organic Polymers with carbon linkers and PolyOligoSiloxySilicones with silicone linkers, bot related to the well-established Porous Organic Polymer material class. These hybrid materials exhibit a unique combination of properties, including chemical inertness, mechanical robustness, hydrophobicity, tunable porosity, flexibility, and customizable chemical functionalization. The synthesis approach starts from zero-dimensional cyclosilicate hydrate and Si-Cl spherosilicate precursors, offering a more efficient synthesis platform for reticular silicate materials compared to the conventional Polyhedral Oligomeric Silsesquioxane precursor. Si-Cl spherosilicates are obtained through the functionalization of silicate cubes from a cyclosilicate hydrate phase using dichlorosilanes. Beyond linker variation in three-dimensional reticular networks, crystallinity was introduced in the zero-dimensional spherosilicate precursor, providing a foundation for the development of crystalline silicate hybrid reticular materials related to Metal-Organic Frameworks and Covalent Organic Frameworks. The precise design of silicate hybrid reticular networks is essential for enhancing their performance in targeted applications, such as gas adsorption and storage in ice-like clathrate hydrates.