Cationic and dicationic 1,2,3-triazolium-based poly(ethylene glycol ionic liquid)s

We report the synthesis of two novel poly(ionic liquid)s having poly(ethylene glycol) main chains and side chains having either one or two 1,2,3-triazolium cations with triethylene glycol spacers and bis(trifluoromethylsulfonyl)imide counter anion(s). Both ion conducting polymers are obtained by post-polymerization sequential modifications, i.e. copper-catalyzed azide–alkyne cycloaddition and N-alkylation of the 1,2,3-triazole group(s), starting from a common poly(ethylene glycol) (PEG) having azidomethyl side groups. The structures of the obtained polymers are supported by 1H NMR spectroscopy and size exclusion chromatography (SEC). The impact of the number of 1,2,3-triazolium groups and the structure of the spacer are discussed based on solubility, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and broadband dielectric spectroscopy (BDS) measurements. The dicationic derivative has a lower glass transition temperature (Tg = −27 °C) as well as higher thermal stability (Td10 = 369 °C) and ionic conductivity (σDC ∼ 10−5 S cm−1 at 30 °C under anhydrous conditions) than the monocationic analogue.