Synthesis, CO2 sorption and capacitive properties of novel protic poly(ionic liquid)s

A series of poly(ionic liquid)s based on the protic monomers obtained by the straight acid-base reaction between the polymerizable 2-(methacryloyloxy)ethyl-phthalic acid and trihexylamine, trioctylamine and dicyclohexylamine have been synthesized and characterized. The assessment of their macromolecular nature is based on FT-IR and 1H NMR spectroscopy, viscosimetry and MALDI-TOF mass spectrometry. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG-DTA) reveal the amorphous behavior of the new poly(ionic liquid)s with a glass transition temperature ranging from ca. 2 to 67 °C and a relatively low thermal stability attributed to the decarboxylation of polyanions. Dynamic contact angles data are consistent with a hydrophilic behavior. Quartz Crystal Microbalance investigations display a fast, reversible and linear response towards CO2, being the dicyclohexylamine-based poly(ionic liquid) the most performing one. Electrochemical impedance spectroscopy investigations on trihexylamine poly(ionic liquid) are also reported.