SunCOChem - PHOTOELECTROCATALYTIC DEVICE FOR SUN-DRIVEN CO2 CONVERSION INTO GREEN CHEMICALS
Published August 18, 2026 | Version v1
Journal article Open

Imidazolium-functionalized polysulfone as a polymeric ionic liquid compatibilizer for ionic-liquid-based gas separation membranes

Authors/Creators

  • 1. Istituto Italiano di Tecnologia (IIT)
  • 2. ROR icon Politecnico di Torino
  • 3. ROR icon EURECAT Centre Tecnològic de Catalunya
  • 4. IoLiTec-Ionic Liquids Technologies GmbH

Description

Functional polymers bearing ionic groups are attractive building blocks for membrane materials because they can simultaneously tailor chain mobility, interfacial interactions, and gas sorption. However, incorporating CO2-philic ionic liquids into glassy polymer matrices often leads to limited phase compatibility and morphological instability, which compromise transport performance and reproducibility.
 
In this work, polysulfone was chemically functionalized with alkyl imidazolium pendants and employed as a polysulfone-derived polymeric ionic liquid (PIL) component in blended membranes containing pristine polysulfone and the ionic liquid 1-butyl-3-methylimidazolium succinimidate ([BMIM][Succ]). By systematically varying the pendant structure while keeping the fabrication protocol constant, we elucidate structure–property relationships linking functional group chemistry to membrane microstructure and gas transport.
 
The imidazolium-functionalized polysulfone markedly improves ionic liquid dispersion and membrane homogeneity, enabling a concurrent increase in CO2 permeability and CO2/N2 selectivity compared to both pristine polysulfone and unmodified polysulfone/ionic liquid blends. CO2 permeability values up to ∼ 290 Barrer at 0.8 bar and 30 °C were obtained. The observed behavior is consistent with an interplay between ionic-liquid-mediated CO2 solubility and PIL-controlled diffusivity through improved phase compatibility.
 
Overall, this study highlights polymeric ionic liquid engineering as a modular functional-polymer strategy to improve phase compatibility in ionic-liquid-containing membranes and tune gas-transport properties through controlled chemical design.

Notes

SunCoChem has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 862192.

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Additional details

Funding

European Commission
SunCoChem - Photoelectrocatalytic device for SUN-driven CO2 conversion into green CHEMicals 862192