Synthesis and characterization of novel fluorinated poly(arylene ether sulfone)s containing pendant sulfonic acid groups for proton exchange membrane materials

Ionomer Membranes Produced from Hexaarylbenzene-Based Partially Fluorinated Poly(arylene ether) Blends for Proton Exchange Membrane Fuel Cells

In this study, a series of high molecular weight ionomers of hexaarylbenzene- and fluorene-based poly(arylene ether)s were synthesized conveniently through condensation and post-sulfonation modification. The use a of blending method might increase the stacking density of chains and affect the formation both of interchain and intrachain proton transfer clusters. Multiscale phase separation caused by the dissolution and compatibility differences of blend ionomer in high-boiling-point solvents was examined through analysis and simulations. The blend membranes produced in this study exhibited a high proton conductivity of 206.4 mS cm−1 at 80 °C (increased from 182.6 mS cm−1 for precursor membranes), excellent thermal resistance (decomposition temperature > 200 °C), and suitable mechanical properties with a tensile strength of 73.8−77.4 MPa. As a proton exchange membrane for fuel cell applications, it exhibits an excellent power efficiency of approximately 1.3 W cm−2. Thus, the ionomer membranes have strong potential for use in proton exchange membrane fuel cells and other electrochemical applications.

Highly Proton-Conducting Membranes Based on Poly(arylene ether)s with Densely Sulfonated and Partially Fluorinated Multiphenyl for Fuel Cell Applications

Series of partially fluorinated sulfonated poly(arylene ether)s were synthesized through nucleophilic substitution polycondensation from three types of diols and superhydrophobic tetra-trifluoromethyl-substituted difluoro monomers with postsulfonation to obtain densely sulfonated ionomers. The membranes had similar ion exchange capacities of 2.92 ± 0.20 mmol g-1 and favorable mechanical properties (Young's moduli of 1.60-1.83 GPa). The membranes exhibited considerable dimensional stability (43.1-122.3% change in area and 42.1-61.5% change in thickness at 80 °C) and oxidative stability (~55.5%). The proton conductivity of the membranes, higher (174.3-301.8 mS cm-1) than that of Nafion 211 (123.8 mS cm-1), was the percent conducting volume corresponding to the water uptake. The membranes were observed to comprise isolated to tailed ionic clusters of size 15-45 nm and 3-8 nm, respectively, in transmission electron microscopy images. A fuel cell containing one such material exhibited high single-cell performance-a maximum power density of 1.32 W cm2 and current density of >1600 mA cm-2 at 0.6 V. The results indicate that the material is a candidate for proton exchange membranes in fuel cell applications.

Sulfonated poly(arylene ether sulfone) functionalized polysilsesquioxane hybrid membranes with enhanced proton conductivity

Sulfopropylated polysilsesquioxane and –COOH containing fluorinated sulfonated poly(arylene ether sulfone) composite membranes (SPAES-SS-X) have been prepared via an in situ sol–gel reaction through the solution casting technique. The composite membranes showed excellent thermal and chemical stability, compared to the pristine SPAES membrane. The uniform dispersion of the sulfonated SiOPS nanoparticles on the polymer matrix was observed from the scanning electron microscope images. Atomic force microscopy and transmission electron microscopy images indicated significantly better phase-separated morphology and connectivity of the ionic domains of the composite membranes than the pristine SPAES membrane. The composite membranes showed considerable improvement in proton conductivity and oxidative stability than the pristine copolymer membrane under similar test conditions.

Synthesis and Characterization of Highly Proton Conducting Sulfonated Polytriazoles

This article describes the synthesis and characterization of highly sulfonated polytriazole copolymers (PTSQSH-I to IV) with IEC_w values ranging from 2.41 to 3.49 mequiv g^-1. The copolymers were synthesized by click reaction between equimolar amount of a dialkyne monomer, potassium 2,5-bis(2-propyn-1-yloxy)benzenesulfonate, and a mixture of two different diazide monomers, 4,4-bis[3'-trifluoromethyl-4'(4-azidobenzoxy)benzyl]biphenyl and 4,4'-diazido-2,2'-stilbene disulfonic acid disodium salt. The copolymers were characterized by Fourier transform infrared and NMR spectroscopy techniques. The membranes were prepared by dissolving the salt form of the copolymers in dimethyl sulfoxide. The copolymers showed high thermal, mechanical, and oxidative stabilities, and the acidified membranes showed very high proton conductivity (43-173 and 132-304 mS cm^-1 at 30 and 80 °C, respectively). Transmission electron microscopy images confirmed the formation of well-phase-separated morphology with interconnected hydrophilic domains (20-150 nm).

Synthesis of novel sulfonated poly(arylene ether)s containing a tetra-trifluoromethyl side chain and multi-phenyl for proton exchange membrane fuel cell application

Herein, a series of novel sulfonated poly(arylene ether)s consisting of tetra-trifluoromethyl-substituted multi-phenyl was synthesized and post-sulfonated to obtain sulfonated polymers with ion exchange capacities ranging from 1.27 to 2.53 mmol g⁻¹.

Synthesis and characterization of highly fluorinated sulfonated polytriazoles for proton exchange membrane application

A series of polytriazole copolymers were synthesized by the click polymerization of fluorinated dialkyne with a mixture of two different diazide monomers and the proton exchange membrane properties of the copolymers were investigated.

Synthesis of Highly Sulfonated Poly(arylene ether) Containing Multiphenyl for Proton Exchange Membrane Materials

A series of sterically hindered, sulfonated, poly(arylene ether) polymers were synthesized by nucleophilic polycondensation reaction using 4,4′′′′-difluoro-3,3′′′′-bistrifluoromethyl-2′′,3′′,5′′,6′′-tetraphenyl-[1,1′;4′,1′′;4′′,1′′′;4′′′,1′′′′]-pentaphenyl and 4,4′-biphenol and were prepared through postpolymerization sulfonation. The chemical structures were confirmed by1H NMR. Subsequent to sulfonation, solvent-casting membranes were provided ion exchange capacity (IEC) values ranging from 0.39 to 2.90 mmol/g. Proton conductivities of membranes ranged from 143 to 228 mS/cm at 80°C under fully humidified conditions which were higher than that of Nafion 117. The membrane also exhibited considerably dimension stability, oxidative stability, and hydrolytic stability. The microphase structure was investigated by transmission electron microscopy (TEM) and the ionic aggregation of sulfonic acid groups exhibited spherical ionic clusters with well-developed phase separated morphology. The results indicated that the membranes are promising candidates for application as proton exchange membranes. This investigation demonstrates introducing multiphenylated moieties to create a high free volume polymer that provides dimensionally stable and high proton conductivity membranes.

Highly proton conducting fluorinated sulfonated poly(arylene ether sulfone) copolymers with side chain grafting

A series of new copolymers HPPQSH-XX PS were synthesized from preformed sulfonated ionomers HPPQSH-XX in order to get high proton conductivity along with other excellent properties.