Ethanol sorption and permeation in fluoropolymer gel membrane containing 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid

This study reports on the sorption and permeation of ethanol vapors in the ionic liquid polymer gel membrane. The gel membrane was based on poly(vinylidene fluoride-co-hexafluoropropylene), which contained 80 wt.% of the imidazolium-based ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Ethanol sorption in ionic liquid membrane was compared with that in the neat polymer. Further, from experimental data followed that the diffusion coefficient of ethanol was 3 orders of magnitude higher in ionic liquid membrane in comparison with neat polymer membrane. Interestingly, ethanol permeability was found immeasurably low in neat polymer membrane while ethanol permeability reached approximately 25,000 Barrer in the ionic liquid membrane at the highest ethanol vapor activity. The values of the activation energy of diffusion and permeation were determined from the temperature dependences of the sorption and permeation experimental data.