Framework Materials as Porous Liquids

Porous liquids have recently been introduced as a new class of material with great potential for gas storage and purification. The permanent porosity and fluid properties of porous liquids provide an avenue for gas storage and transportation that avoids the processing restrictions of solid porous materials. Despite the promise of porous liquids, only a handful of these materials have been realized to date. This work develops porous liquids from covalent organic frameworks (COFs). Colloidal 3D imine-based COFs are synthesized with particle size control down to 60 nm. The colloidal COFs are suspended in a bulky ionic liquid solvent that is size-excluded from entering the COF pore, demonstrating a Type 3 porous liquid. Gas sorption studies are used to determine the gas uptake and adsorption enthalpy of hydrogen and other gases in the porous liquid. This work presents a new type of tunable organic porous liquid that can be used for gas storage and separation.