Relative Chemical Stability of Imidazolium-Based Alkaline Anion Exchange Polymerized Ionic Liquids Academic Article uri icon

abstract

  • We thoroughly investigate and quantify the chemical stability of an imidazolium-based alkaline anion exchange polymerized ionic liquid (PIL), poly(1-[(2-methacryloyloxy)ethyl]-3-butylimidazolium hydroxide) (poly(MEBIm-OH), over a broad range of humidities, temperatures, and alkaline concentrations using the combined techniques of electrochemical impedance spectroscopy and nuclear magnetic resonance spectroscopy. High chemical stability was observed under dry conditions (10% RH) at 30 C, humid and saturated conditions up to 80 C, and even in mild alkaline conditions ([KOH] < 1 M) at 25 C. Degradation was only observed under more vigorous conditions: dry conditions (10% RH) at 80 C or at higher alkaline concentrations ([KOH] > 1 M). Under these conditions, we suggest an imidazolium ring-opening mechanism as the primary degradation pathway, based on a detailed analysis of the 1H NMR spectra. Similar to poly(MEBIm-OH), other alkaline anion (carbonate (CO 32-) and bicarbonate (HCO3-)) exchange PILs were also synthesized in this study via salt metathesis of the PIL precursor, poly(1-[(2-methacryloyloxy)ethyl]-3-butylimidazolium bromide) (poly(MEBIm-Br)). The thermal and ion conductive properties of each PIL in this study were characterized. The ionic conductivity of the hydroxide conducting PIL, poly(MEBIm-OH), was the highest of these PILs investigated at 9.6 mS cm-1 at 90% RH and 30 C with an Arrhenius activation energy of 17.1 kJ mol-1 at 90% RH. 2011 American Chemical Society.

published proceedings

  • Macromolecules

altmetric score

  • 6

author list (cited authors)

  • Ye, Y., & Elabd, Y. A.

citation count

  • 233

complete list of authors

  • Ye, Yuesheng||Elabd, Yossef A

publication date

  • November 2011