Novel Ionic Conducting Composite Membrane Based on Polymerizable Ionic Liquids

Abstract

In this work, the design and characterization of new supported ionic liquid membranes, as medium-temperature polymer electrolyte membranes for fuel-cell application, are described. These membranes were elaborated by the impregnation of porous polyimide Matrimid® with different synthesized protic ionic liquids containing polymerizable vinyl, allyl, or methacrylate groups. The ionic liquid polymerization was optimized in terms of the nature of the used (photo)initiator, its quantity, and reaction duration. The mechanical and thermal properties, as well as the proton conductivities of the supported ionic liquid membranes were analyzed in dynamic and static modes, as a function of the chemical structure of the protic ionic liquid. The obtained membranes were found to be flexible with Young’s modulus and elongation at break values were equal to 1371 MPa and 271%, respectively. Besides, these membranes exhibited high thermal stability with initial decomposition temperatures > 300 °C. In addition, the resulting supported membranes possessed good proton conductivity over a wide temperature range (from 30 to 150 °C). For example, the three-component Matrimid®/vinylimidazolium/polyvinylimidazolium trifluoromethane sulfonate membrane showed the highest proton conductivity—~5 × 10−2 mS/cm and ~0.1 mS/cm at 100 °C and 150 °C, respectively. This result makes the obtained membranes attractive for medium-temperature fuel-cell application.

Novel Ionic Liquid/Polyetherimide Composite Membranes: The Interplay of Transport Properties and Membrane Structure

“…Subsequently, the problem of exudation could be successfully mitigated with polymers engaging in interchain interactions via of hydrogen-bonding. This phenomenon has been extensively studied in the literature and has proven to be an effective strategy for improving the gas transport properties of polyimide membranes [20][21][22].…”

Different Approaches for the Preparation of Composite Ionic Liquid-Based Membranes for Proton Exchange Membrane Fuel Cell Applications—Recent Advancements

“…Moreover, the impregnated membranes demonstrated good mechanical features such as Young’s modulus and elongation at break of 0.3 to 21.4 MPa and 6 to 174%, respectively. In another research study, Kobzar et al [ 64 ] prepared composite membranes based on ILs and polyimide Matrimid ® polymer. The elaboration of composite membranes was performed by impregnation of porous polyimide membranes with three different ILs and one polymerized IL (PIL) – vinyl imidazolium trifluoromethane sulfonate [VIm][Tf], allyl imidazolium trifluoromethane sulfonate [AIm][Tf], methacrylate imidazolium trifluoromethane sulfonate [MIm][Tf], and polymerized vinyl imidazolium trifluoromethane sulfonate [PVIm][Tf].…”