Hydroxide Conducting Polymerized Ionic Liquid Block Copolymers for Alkaline Fuel Cells

In previous work in our laboratory, we reported on the chemical stability of an imidazolium-based hydroxide conducting 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 [1]. This polymer provides a good building block for future investigations since chemical stability of hydroxide conducting polymers is a significant issue as it pertains to long-term alkaline fuel cell (AFC) operation. In this talk, we will present the hydroxide conductivity and morphology of a series of PIL diblock copolymers, poly(MMA-b-MEBIm-OH), composed of the IL monomer, MEBIm-OH, and the non-ionic monomer, methyl methacrylate (MMA), at various PIL compositions. PIL block copolymers conjoin the advantages of block copolymers and PILs: self-assembled nanostructured morphologies and unique electrochemical properties. To date, there are few reports of PIL block copolymers in the literature. Therefore, a fundamental understanding of morphology and ion transport in these materials will be highly beneficial, specifically for the optimization of AFC performance.

1. Ye, Y.; Elabd, Y.A. Relative Chemical Stability of Alkaline Exchange Polymerized Ionic Liquids. Macromolecules 2011, 44 (21), 8494-8503.