Influence of the bisphenol structure on the direct synthesis of sulfonated poly(arylene ether) copolymers. I

Hydrocarbon-Based Composite Membrane Using LCP-Nonwoven Fabrics for Durable Proton Exchange Membrane Water Electrolysis

A new hydrocarbon-based (HC) composite membrane was developed using liquid crystal polymer (LCP)-nonwoven fabrics for application in proton exchange membrane water electrolysis (PEMWE). A copolymer of sulfonated poly(arylene ether sulfone) with a sulfonation degree of 50 mol% (SPAES50) was utilized as an ionomer for the HC membranes and impregnated into the LCP-nonwoven fabrics without any surface treatment of the LCP. The physical interlocking structure between the SPAES50 and LCP-nonwoven fabrics was investigated, validating the outstanding mechanical properties and dimensional stability of the composite membrane in comparison to the pristine membrane. In addition, the through-plane proton conductivity of the composite membrane at 80 °C was only 15% lower than that of the pristine membrane because of the defect-free impregnation state, minimizing the decrease in the proton conductivity caused by the non-proton conductive LCP. During the electrochemical evaluation, the superior cell performance of the composite membrane was evident, with a current density of 5.41 A/cm² at 1.9 V, compared to 4.65 A/cm² for the pristine membrane, which can be attributed to the smaller membrane resistance of the composite membrane. From the results of the degradation rates, the prepared composite membrane also showed enhanced cell efficiency and durability during the PEMWE operations.

Experimental and Computational Approaches to Sulfonated Poly(arylene ether sulfone) Synthesis Using Different Halogen Atoms at the Reactive Site

Engineering thermoplastics, such as poly(arylene ether sulfone), are more often synthesized using F-containing monomers rather than Cl-containing monomers because the F atom is considered more electronegative than Cl, leading to a better condensation polymerization reaction. In this study, the reaction's spontaneity improved when Cl atoms were used compared to the case using F atoms. Specifically, sulfonated poly(arylene ether sulfone) was synthesized by reacting 4,4'-dihydroxybiphenyl with two types of biphenyl sulfone monomers containing Cl and F atoms. No significant difference was observed in the structural, elemental, and chemical properties of the two copolymers based on nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and electrochemical impedance spectroscopy. However, the solution viscosity and mechanical strength of the copolymer synthesized with the Cl-terminal monomers were slightly higher than those of the copolymer synthesized with the F-terminal monomers due to higher reaction spontaneity. The first-principle study was employed to elucidate the underlying mechanisms of these reactions.

Nano-enhanced sulfonated poly(arylene ether sulfone) composite membranes and their characterization

Chlorine is a widely used oxidizing agent in desalination to control bacteria that cause biofouling. The lack of chlorine resistance in commercial desalination membranes urged the development of an alternate polymer material. In this study, commercially available copolymer (SES0005, AquafoneTM), resistant to dissolved chlorine in water, has theoretical IEC of 2.08 meq.g-1 is blended with 0.5-15 %(w/w) TiO2 nanoparticles of <25 nm diameter and 45-55 m2.g-1 surface area by using ball milling device. SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy) result supports TiO2 content and uniform distribution. The chlorine stability of membranes was evaluated in sodium hypochlorite solution from 100 to 2000 ppm (pH 9). TGA and FT-IR analysis were performed for these membranes. The 1.5 %(w/w) TiO2 nano-enhanced membrane water retention is 23 % which is ∼53 % higher than that of pristine (15 %) membrane. Tensile strength of pristine and 0.5 %(w/w) TiO2 nano-enhanced membrane is 23, and 44 MPa, respectively. TiO2 nanoparticle addition improved dimensional and mechanical properties. This study attempts to correlate the SES polymer-TiO2 interactions with the characterization techniques.

Role of Doping Agent Degree of Sulfonation and Casting Solvent on the Electrical Conductivity and Morphology of PEDOT:SPAES Thin Films

Poly(3,4-ethylenedioxythiophene) (PEDOT) plays a key role in the field of electrically conducting materials, despite its poor solubility and processability. Various molecules and polymers carrying sulfonic groups can be used to enhance PEDOT's electrical conductivity. Among all, sulfonated polyarylether sulfone (SPAES), prepared via homogenous synthesis with controlled degree of sulfonation (DS), is a very promising PEDOT doping agent. In this work, PEDOT was synthesized via high-concentration solvent-based emulsion polymerization using 1% w/w of SPAES with different DS as dopant. It was found that the PEDOT:SPAESs obtained have improved solubility in the chosen reaction solvents, i.e., N, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone and, for the first time, the role of doping agent, DS and polymerization solvents were investigated analyzing the electrical properties of SPAESs and PEDOT:SPAES samples and studying the different morphology of PEDOT-based thin films. High DS of SPAES, i.e., 2.4 meq R-SO₃^-× g^-1 of polymer, proved crucial in enhancing PEDOT's electrical conductivity. Furthermore, the DMSO capability to favor PEDOT and SPAES chains rearrangement and interaction results in the formation of a polymer film with more homogenous morphology and higher conductivity than the ones prepared from DMAc, DMF, and NMP.

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.

Novel cross-linked poly(vinyl alcohol)-based electrolyte membranes for fuel cell applications

A series of cross-linked poly(vinyl alcohol)-sulfonated poly(ether sulfone) blend membranes were prepared. The studies of physico-chemical properties revealed that the reported membranes are promising candidate for PEMFC applications.

A novel proton conducting polymer electrolyte membrane for fuel cell applications

A series of phenolphthalein-based sulfonated poly(ether ether sulfone) (SPEES) membranes were synthesized by aromatic nucleophilic polymerization reaction. The degree of sulfonation was controlled by direct synthesis of sulfonated polymer, which leads to high thermal stability. The physicochemical properties of the SPEES membranes were studied in order to evaluate the suitability of these membranes in fuel cell applications. The ion-exchange capacity of the synthesized SPEES membranes was found in the range between 2.19 mequiv. g−1 and 2.35 mequiv. g−1. The morphology of the membranes was investigated with high-resolution scanning electron microscopy and confirmed the presence of hydrophilic domains that impart good proton conductivity. The membrane electrode assembly of SPEES-30 and SPEES-50 membranes has been successfully fabricated, where SPEES-50 produced a maximum peak power density of 643 mW cm−2 while applying in hydrogen–oxygen fuel cell.

Sulfonated Poly(Arylene Ether Sulfone) Copolymers - Acid and Salt Form: Potential Biofunctional Polymers

The synthesis, characterization and preliminary evaluation of the potential for biofunctionality of strong, ductile sulfonated poly(arylene ether sulfone) copolymers of controlled hydrophilicity are described herein. A series of film forming random (statistical) copolymers were made from 4,4'-biphenol and a stoichiometric mixture of 3,3'-disulfonated and non-sulfonated 4,4'-dichlorodiphenyl sulfone; the degree of disulfonation varied from 10-60%. The copolymers were characterized by intrinsic viscosity, DSC, TGA and molecular weight (GPC). Preliminary evaluation of the potential of these copolymers in the acid or basic salt form for biocompatibility and biomedical applications was conducted via water uptake and contact angle measurements. The copolymers were cast into films from 10wt. percentage solutions in DMAc. Films were converted from the salt form to the acid form through treatment with concentrated H2SO4, and from acid form to sodium salt form by treatment with base. The surface of the films were characterized by XPS that confirmed full conversion to the intended form. The water uptake measurements showed that the acid form absorbed a maximum of ~ 800wt. percentage, and the salt forms absorbed a maximum of ~70 to 100wt. percentage. The contact angle between a water droplet and the surface of the copolymer films in the potassium salt form was measured using the Sessile Drop method, and it decreased as a function of the degree of sulfonation, in the range of 80-40o. The possibility of applications in pH-sensitive drug delivery systems is suggested.

Monovalent cation selective crown ether containing poly(arylene ether ketone)/SPEEK blend membranes

Crown ether units incorporated in the poly(arylene ether ketone) (PAEK) main chain enhance the miscibility of PAEK with sulfonated poly(ether ether ketone) (SPEEK). The resulting blend membranes enable the separation of monovalent ions.

Chlorine resistant glutaraldehyde crosslinked polyelectrolyte multilayer membranes for desalination

Crosslinked polyelectrolyte multilayer membranes are synthesized with salt rejection values approaching those of commercial desalination membranes, but with increased chlorine resistance. The membranes are fabricated directly onto porous commercial substrates. Subsequent crosslinking of the polycation layers with glutaraldehyde leads to NaCl rejections of up to 97%, while the incorporation of a highly sulfonated polysulfone polyanion leads to high chlorine resistance.

Synthesis and properties of sulfonated poly(arylene ether ketone sulfone) copolymer

A series of novel sulfonated poly(arylene ether ketone sulfone)s copolymer (SPAEKS- x) were synthesized by polycondensation reaction of commercial 2,2-bis(4-hydroxyphenyl)propane, 4,4′-dichlorodiphenylsulfone, 4,4′-dihydroxydiphenylether, and 3,3′disulfonate-4,4′-difluorobenzophenone. The degree of sulfonation was realized by controlling quantities of the sulfonated monomer. The structure of SPAEKS- x was confirmed by proton nuclear magnetic resonance and Fourier transform infrared instrument. The tough, flexible, and transparent films of SPAEKS- x were obtained by solution casting. These membranes with desired ion-exchange capacity (IEC) values showed good thermal stability and mechanical properties. The proton conductivity of SPAEKS- x with the IEC of 1.44 meq. g−1 is very close to that of Nafion 117 in a temperature range from 20°C to 100°C. SPAEKS- x copolymers, which combine the advantages of the sufficiently high proton transport conductivity and enhanced physical properties, will be the potential alternative materials to Nafion for proton exchange membrane fuel cell.

High proton conductivity of sulfonated methoxyphenyl-containing poly(arylene ether ketone) for proton exchange membranes

A polyelectrolyte membrane based on sulfonated methoxyphenyl-containing poly(arylene ether ketone) (SMP-PAEK) was obtained, which exhibited suitable proton conductivities and excellent mechanical properties.

Fully aromatic naphthalene-based sulfonated poly(arylene ether ketone)s with flexible sulfoalkyl groups as polymer electrolyte membranes

Naphthalene-based poly(arylene ether ketone)s with pendant sulfoalkyl groups were prepared by a demethylation and sulfobutylation method. They exhibited high proton conductivity, low methanol permeability and high thermal stability.

Liquid crystal alignment behavior on sulfonated poly(arylene ether sulfone) films

A series of sulfonated poly(arylene ether sulfone) (PAES#, # is the feed monomer ratio of 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone) derivatives were synthesized to investigate the liquid crystal (LC) alignment property of these polymer films.

Sulfonated carbon nanotubes synergistically enhanced the proton conductivity of sulfonated polyarylene ether nitriles

The effect of sulfonated carbon nanotubes using an acyl chloride method on proton conductivity of sulfonated polyarylene ether nitriles was investigated.