Synthesis of anion-functionalized mesoporous poly(ionic liquid)s via a microphase separation-hypercrosslinking strategy: highly efficient adsorbents for bioactive molecules

Abstract

The synthesis of porous materials with a well-defined pore structure and functionality is centrally important for the development of advanced adsorbents and sensors. In this study, we explore a direct and facile methodology combining microphase separation and hypercrosslinking, and prepare anion-functionalized mesoporous poly(ionic liquid)s (MPILs) with well-developed mesopores. This methodology involved a copolymerization of IL monomers and crosslinkers to create mesopores via microphase separation. Additionally, the MPILs were texturally engineered by hypercrosslinking to stabilize/rebuild labile collapsed mesoporous networks and generate microporosity. Thus, a new family of anion-functionalized MPILs containing amphiphilic long-chain carboxylate ionic liquids (LCC-ILs) were synthesized. These anion-functionalized MPILs exhibited extraordinarily high adsorption capacity (211.45 mg g⁻¹ for tocopherols) and excellent selectivity (S_δ/α, 8.65; S_β&γ/α, 4.20) for bioactive tocopherol homologues and organic phenolic compounds with high structural similarity, significantly better than those of commercial adsorbents or common MPILs. Additionally, anion-functionalized MPILs demonstrated enhanced carbon dioxide (CO₂) capture performances (28.18 mg g⁻¹ at 0 °C and 1 bar). This study demonstrates the great potential of anion-functionalized MPILs as advanced adsorbents, and facilitates a textural engineering approach to the development of novel porous ionic materials for other applications.