Type I Porous Liquids with Super-Low Viscosities: the Construction through a Rather Simple One-Step Covalent Linkage Strategy and Its Facile Regulation by a Mixed-Ligand Strategy

Porous liquids (PLs) are a novel class of flowing liquid systems that possess accessible permanent porosity, exhibiting great prospects in gas capture and separation. Nevertheless, the further development of PLs lies in the facile synthesis and regulation of PLs with low viscosities. Herein, a novel strategy of preparing type I PLs with super-low viscosity is proposed through a simple one-step covalent linkage reaction using UiO-66-NH₂ as the pore generator and monoglycidyl ether terminated polydimethylsiloxane (E-PDMS) as the sterically hindered solvent, respectively. More importantly, the idea that PLs can be regulated like advanced porous materials (APMs) is proposed and demonstrated, that is, PLs can be regulated by modulating pore generators with the mixed-ligands method. As expected, the resultant PLs not only demonstrate a promising potential in CO₂ sorption as a flowing sorbent but also exhibit a superior CO₂/N₂ selective separation. Meanwhile, positron annihilation lifetime spectrum (PALS) and molecular dynamics (MD) simulations further verify the accessible permanent porosity and the favorable CO₂ selective sorption. This work provides a simple and facile method to prepare type I PLs with super-low viscosities, shedding light on the precise regulation of PLs toward task-specific applications.