Tailored Gas–Solid Interfacial Selectivity of Porous Polyionic Liquid Monoliths for High-Efficiency PM Interception and Accurate CO₂ Sieving

The high intrinsic viscosity of liquid-state ionic liquids (ILs) significantly impedes their application in the coseparation of CO₂ and PM from flue gas, as this attribute leads to diminished adsorption capacity and substantial energy consumption. Herein, we present a direct phase transition synthesis strategy that enables single-step conversion of ILs from liquid to solid states through radical polymerization, thereby fabricating monolithic imidazolium-based porous polyionic liquids (VEs) with charge-pore synergy for efficient flue gas separation. The three-dimensional hierarchical porous networks within monolithic VEs feature internal high-flux mass transfer channels, enhancing permeation efficiency under Knudsen diffusion and Fick's law. Density functional theory simulations quantitatively confirm the intensified dipole polarization in VEs, elucidating the electrostatic adsorption mechanism responsible for their significantly increased adsorption capacity compared to liquid-state ILs. On this basis, fluent simulations reveal dynamic flow field characteristics of monolithic VEs, visualizing diffusion processes for CO₂/PM under field interactions. This direct phase transition engineering strategy provides innovative insights into designing high-performance bifunctional CO₂/PM adsorbents.