AbstractIn this study, two new water‐soluble poly ionic liquids (PILs) polyethylene glycol‐ Di choline chloride (PEG‐(ChCl)2) were modified, with two molecular weights of PEG, 400 and 600, to be used as solvents for CO2 capture. The modified polymers were characterized using Fourier transform infra‐red (FT‐IR) spectroscopy and proton nuclear magnetic resonance (1H‐NMR). CO2 absorption using the PILs was conducted at temperatures from 30 to 70°C and at pressures ranging from 10 to 13 bars. Both PILs saturated and then regenerated under the regeneration temperature: 90–100°C. The results showed that most of CO2 in the liquid phase is released through the thermal regeneration before solutions start to boil after three cycles. PEG (400)–(ChCl)2, and PEG(600)–(ChCl)2 with a concentration of 0.03M showed CO2 loading of 16.24 and 15.68, respectively. These results were 25% higher than the original PEG (400–600). © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.