Nanoporous and proton conductive hydrophobic–hydrophilic copolymer thermoset membranes

Abstract

Copolymers of hydrophobic diglycidyl ether of bisphenol A (DGEBA) vinyl ester (VE) and hydrophilic 2‐acrylamido 2‐methyl 1‐propane sulfonic acid (AMPS) were evaluated as proton conducting membranes for fuel cell applications. Membranes were synthesized using free radical copolymerization in the presence of a common solvent for both monomers, dimethyl formamide (DMF), followed by solvent removal by supercritical CO2 to induce porosity. Micrographs revealed pore sizes below 60 nm with porosity proportional to the initial solvent fraction used. Studies on the states of water showed that the presence of this pore volume significantly altered the freezable water fraction at equivalent AMPS concentrations. Comparison of the moles of water per mole of sulfonic acid (λ) between copolymer membranes and AMPS monomer solutions showed that the nonfreezable water (λ|nonfr) was depressed at high AMPS concentrations, suggesting that differences in interatomic distances between sulfonic acid groups might alter λ|nonfr. The highest average through plane conductivity of membranes was determined to be 30 mS/cm and was comparable to that of Nafion®117 (27 mS/cm). The effective proton mobility, μeff, was calculated and suggested to be a parameter used to capture the effects of membrane structure and swelling while acting as a comparison between different membrane types. Fuel cell tests on membranes at low ion exchange capacities were compared to Nafion®117, with suggestions on improvements of copolymer structures for improved performance. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1245–1255, 2010

Synthesis and Characterization of Ionic Polymer Networks in a Room-Temperature Ionic Liquid

“…This polymer system uses AMPS and a vinyl ester resin based on a catalyzed methacrylated 4,4’ diglycidyl ether of bisphenol A, instead of MBA, as the cross-linking agent. Rahmathullah has reported conductivities in the range of 1.00 mS cm –1 to 27 mS cm –1 , which has a considerably higher maximum than the conductivities for the ILGs. , …”

“…In this study, ILGs were generated via a free radical copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and N , N ′-methylene(bis)acrylamide (MBA) using 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO 4 ]) as a RTIL solvent medium. Because of AMPS and MBA being extensively studied in responsive hydrogel systems and the ability of AMPS to conduct protons via the sulfonic acid moiety as well as possessing excellent solvent uptake and retention properties, AMPS and MBA (Scheme ) were selected as the monofunctional and bifunctional monomers, respectively, to produce hydrogel-like polymeric materials that incorporate a unique solvent medium. − Fundamental physical properties of the ILGs such as the glass transition temperature, mechanical modulus, swelling, and ionic conductivity were examined. The intention of this study was to synthesize and characterize polymer gels that contain ionic character not only in the solvent medium but also in the polymer network with the potential to support ion transport and separation applications.…”

Hierarchically Structured Nanoporous Poly(Ionic Liquid) Membranes: Facile Preparation and Application in Fiber-Optic pH Sensing

“…Porous polymeric membranes are receiving increasing research interest in both academia and industry because such systems build up a multifunctional platform for fundamental research and many practical usages . In this regard, porous polyelectrolyte membranes (PPMs) are particularly appealing because the additionally introduced charged character, along with their high mechanical and chemical stability, renders them versatile for device fabrication and attractive applications such as separation, controlled release, catalyst supports, biointerfacing, and sensors, just to name a few . In industry, there are already two well-established methods for preparing porous membranes, namely, non-solvent-induced phase separation (NIPS) and thermally induced phase separation (TIPS) .…”

SPEEK‐Tin dioxide proton conducting membranes: Effect of modifying agent of tin dioxide particles surface

“…However, the amount of water which can be absorbed by the membrane is limited by its mechanical and chemical stability. [ 51–53 ]…”