Materials whose chemical structures are comprised of molecules linked by covalent bonds into extended structures may be placed into two classes: (1) polymers and cross-linked polymers, and (2) covalent organic frameworks (also known as covalently linked organic networks).
The first class, polymers and cross-linked polymers, is typically embodied by polymerization of molecular monomers to form long linear chains of covalently-bonded molecules. Polymer chemistry processes can allow for polymerized chains to, in turn, or concomitantly, become ‘cross-linked.’ The nature of polymer chemistry offers poor control over the molecular-level structure of the formed material, i.e. the organization of polymer chains and the patterning of molecular monomers between chains is mostly random.
Integrating fluorine content into polymers and cross-linked polymers opens opportunities for adapting/improving their utility. However, this is generally not a straightforward procedure: blending Teflon, Viton, or custom fluorinated polymers can be challenging due to their poor solubility with the nominal components of a film and may not result in evenly dispersed fluorine content. Integrating fluorinated small molecules is generally a more facile option; however achieving a stable dispersion (where the fluorine is evenly distributed) and the propensity for phase separation and leaching from the film are common road blocks toward implementation.
The second class, covalent organic frameworks (COFs), differ from the first class (polymers/cross-linked polymers) in that COFs are intended to be highly patterned. In COF chemistry molecular components are called molecular building blocks rather than monomers. During COF synthesis molecular building blocks react to form two- or three-dimensional networks. Consequently, molecular building blocks are patterned throughout COF materials and molecular building blocks are linked to each other through strong covalent bonds.
COFs developed thus far are typically powders with high porosity and are materials with exceptionally low density. While these conventional COFs are useful, there is a need, addressed by embodiments of the present invention, for new film materials where fluorine can be readily integrated (e.g., chemically bonded) and evenly dispersed within their structures. The fluorinated SOFs of the present disclosure address these needs and allow for the fluorine content to be logically and easily adjusted.