(618c) Tailoring Dual Anionic-Cationic Poly(ionic liquid) Composite Membranes for Advanced CO2 Separation

Herein, we propose a strategy of developing novel dual anionic-cationic crosslinked poly(IL)-IL composite membranes via a photopolymerization method for enhanced CO₂ separations. Interestingly, these are the first examples of dually photopolymerized anionic-cationic poly(IL)-IL composite systems, in which the backbones of poly(IL)s feature both pendant anions and cations without any mobile counterions unlike poly(IL) reported so far in the literature. A new type of dual photopolymerizable anionic-cationic IL (DIL) monomer having methacrylate functional group tethered with highly delocalized sulfonimide anion (–SO₂–N^(-)–SO₂–C₇H₇) and a vinylimidazolium counterion ([C₄vim]⁺) was successfully synthesized and photopolymerized with four distinct amounts of free IL with a structurally analogous cation ([C₄mim][Tf₂N]) and 20 wt% PEGDA crosslinker, offering novel composite matrices. All of the newly developed poly(IL)-IL composite membranes exhibited superior CO₂/CH₄ and CO₂/N₂ selectivities together with moderate CO₂/H₂ selectivity and reasonable CO₂ permeabilities. A “bottom-up” approach of our novel poly(IL) systems on their structure-property relationships as well as gas separation properties will be discussed in this presentation.