Absorption of CO₂ in lyotropic liquid crystals

Abstract

Vapor-liquid equilibria data of three poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)/water liquid crystals (LCs) with CO 2 has been obtained up to 6 bar. The investigated LCs consist of 60% (EO) 3 (PO) 50 (EO) 3 (Pluronic L81), 70% (EO) 8 (PO) 47 (EO) 8 (Pluronic L92), and 70% L92-NH 2. The maximum CO 2 loading of the LCs was 5-13 g CO 2 /kg sample. Pure L81 and L92 displayed higher absorption of CO 2 than the LCs. Rheology measurements revealed that the increasing viscosity of the samples decreases the CO 2 loading. Water diffusion in the LCs was qualitatively investigated by nuclear magnetic resonance, confirming that free water and tightly bound water are present in the LCs.