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A series of sulfonated poly(arylene ether sulfone) block copolymers with aliphatic chains (SPAES-LA) to lend structural flexibility in the polymer backbone have been synthesized to prepare proton exchange membranes (PEMs) showing improved electrochemical performance and dimensional/oxidative stabilities. The SPAES-LAs, bearing different hydrophilic/hydrophobic segment lengths, are prepared via polycondensation and sulfonation reactions. The sulfonation reaction occurs in specific fluorenylidene units by using chlorosulfonic acid. The SPAES-LA membrane, fabricated by solvent casting method, exhibits remarkable dimensional/thermal stabilities. Moreover, proton conductivity of as-prepared SPAES-LA membranes demonstrates significant improvement with expansion of ion clusters which is due to the increased hydrophilic volume ratio. In particular, the SPAES-LA-X12Y28 membrane exhibited heightened proton conductivity of 158.4 mS cm−1 as well as suitable dimensional stability and durability towards radical oxidation, due to an effective well-defined hydrophilic-hydrophobic interface. Furthermore, H 2 /O 2 fuel cell performance using SPAES-LA-X12Y28 membrane achieves a maximum power density of 232.02 mW cm−2, a result which points out that SPAES-LA membranes show great potential for applications of polymer electrolyte membrane. Image 1 • The block copolymers are synthesized via controlling oligomer lengths. • The fabricated membranes show desirable thermo-oxidative stability. • The membranes showed high physio-chemical properties. • The as-prepared membranes exhibit high ionic conductivity and unit-cell performance. [ABSTRACT FROM AUTHOR]

Summary: Organic‐inorganic composite membranes were prepared by introducing silicon dioxide (SiO2) or functionalized SiO2 (ƒ‐SiO2) with various particle sizes into sulfonated poly (arylene ether ketone) (SPAEK) containing pendant groups, and the membrane was manufactured via directly casting which is a cost‐competitive method. The structure and morphology of the composite membranes were confirmed by 1H NMR, FT‐IR, XRD, and FE‐SEM analysis which demonstrated that inorganic nanofillers were successfully introduced. The FE‐SEM surface images showed that SiO2 and ƒ‐SiO2 particles were very well dispersed within the membrane sheets. The water uptake and swelling ratio of the composite membranes including SiO2 or ƒ‐SiO2 almost did not change when compared with the pristine SPAEK membrane. All fabricated membranes demonstrated good thermal/dimensional stabilities, robust mechanical behavior, and excellent proton conductivity. In particular, the SPAEK/ƒ‐SiO2 composite membranes exhibited improved ionic conductivity compared with the pristine membrane at 70% relative humidity (RH) due to hydrogen bonding between ─SO3H groups of functionalized inorganic filler and polymer backbone. Furthermore, the maximum power density of SPAEK/ƒ‐SiO2 reached as high as 273.11 mW cm−2 at 60°C under 70% RH. Therefore, the composite membranes with ƒ‐SiO2 testify to great potential as polymer electrolyte membrane. [ABSTRACT FROM AUTHOR]

Abstract A series of composite membranes for application as anion exchange membranes were prepared by introducing various amounts (0.1–5.0 wt%) of reduced graphene oxide (rGO) into chloromethylated poly(arylene ether ketone) (CM-PAEK), followed by quarternization and anionization. CM-PAEK/rGO composite membranes with controlled weight ratios of rGO were fabricated by cost-competitive solution casting method. The field emission scanning electron microscopy (FE-SEM) images of the composite membranes showed that the distribution of rGO was uniform, and the prepared membranes have similar thicknesses confirmed by the cross-sectional image. The composite membranes exhibited enhanced the mechanical strength due to π-π interaction between the aromatic chain of rGO and the polymer backbone, and after the quaternization, hydroxide conduction was improved by hydrogen bonding between rGO and functional ammonium groups. Among the QN-PAEK/rGO membranes with various amounts of rGO, QN-PAEK/rGO 1.0 wt% demonstrated the highest ionic conductivity of 115 mS cm−1, and other composite membranes, which were blended more than that (3 wt% and 5 wt%), showed a decrease in ionic conductivity due to aggregation of inorganic nano fillers. Furthermore, alkaline resistance, mechanical strength, and dimensional stability of composite membranes have been greatly improved due to the introduction of rGO, which demonstrate great potential application as anion exchange membrane for fuel cells. Graphical abstract Image 1 Highlights • QN-PAEK/rGO composite membranes were prepared by introducing various amount of rGO. • The QN-PAEK/rGO composite membranes demonstrated superior OH− conductivity. • The prepared membranes showed improved mechanical and dimensional stabilities. • The membranes exhibited remarkable alkaline stability in a 2 M NaOH solution for 600 h. [ABSTRACT FROM AUTHOR]

Here, we present a series of organic-inorganic composite membranes using graphitic carbon nitride (gC 3 N 4) derivatives (porous (p-) gC 3 N 4) and F-doped porous (F-p-) gC 3 N 4) to improve the electrochemical properties and dimensional stability for anion exchange membranes (AEMs). The introduction of F-p-gC 3 N 4 onto a quaternized poly(phenylene oxide) (QPPO) matrix induced the expansion of the ion channel by promoting nanophase separation, and the composite membranes possess high ion conductivity (>142.1 mS cm−1 at 90 °C, i.e., 1.75 times as high as the pristine membrane) and suitable alkaline durability (>74% ion conductivity in 1 M KOH at 80 °C for 30 days) with enhanced dimensional change. Importantly, H 2 -O 2 fuel cell performance of QPPO/F-p-gC 3 N 4 -0.5 reached a maximum peak power density of 286.2 mW cm−2 at 60 °C. In addition, the QPPO/F-p-gC 3 N 4 -0.5-based membrane electrode assembly can be operated under 0.15 A cm−2 current density at 60 °C for 100 h. Thus, this strategy could be suitable for future work on AEM applications. [Display omitted] • The F-doped porous gC 3 N 4 (F-p-gC 3 N 4) was prepared for anion exchange composite membranes. • The composite membrane showed superior ion conductivity of 142.1 mS cm−1 with suitable dimensional stability. • The ion conductivity of composite membrane was well-retained after alkaline stability >30 days in 1 M KOH at 80 °C. • The H 2 -O 2 fuel cell performance exhibited the highest peak power density of 286.2 mW cm−2. • The prepared composite membrane exhibited long-term stability at 60 °C for 100 h. [ABSTRACT FROM AUTHOR]

A new series of partially fluorinated and sulfonated poly(biphenylsulfone ketone) block copolymers as proton exchange membrane materials were prepared from hydrophilic and hydrophobic oligomers. The copolymers were characterized by proton NMR, FT-IR, GPC, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) thermograms. The membranes showed excellent thermal and oxidative stability; e.g., TGA and DSC demonstrated that all sulfonated block copolymers exhibited good thermal stability with an initial weight loss at temperatures above 200 °C. Block-30 membranes showed low water uptake and acceptable ionic exchange capacity (IEC). The proton conductivity of the block-30 was 75 mS cm−1 at 90 °C and 100% relative humidity (RH), while Nafion-117 had a value of 98 mS cm−1 under the same conditions. AFM analysis of the Block-30 clearly showed that the morphology of the membranes separated the hydrophilic and hydrophobic domains which provided an effective proton-transport pathway. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and properties of densely sulfonated poly(arylene biphenylsulfone ketone) block copolymer and its composite membranes including phosphotungstic acid (PWA) were investigated. The chemical structure of the block copolymers was characterized by FT-IR, 1H-NMR, and GPC. The block copolymer composite membranes were prepared by mixing the block copolymer with a commercial PWA. The composite membranes have shown not only good thermal stability (decomposition temperature in nitrogen >250°C), but also lower water uptake than the unfilled membranes. Their crystalline phases and morphologies have been confirmed by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FSEM), respectively. The composite membranes displayed relevant ion exchange capacity (IEC), as well as good proton conductivity especially at elevated temperature. The proton conductivity of the Block-19/PWA-30 composite membrane (IEC 1.58meqg−1) reached the maximum of 97mScm−1 at 90°C under 100% relative humidity (RH), which is comparable to Nafion-117. The fabricated composite membrane exhibited a maximum fuel cell power density of 150mWcm−2, which was much higher that of Block-19 membrane and can be considered as a candidate for potential application in fuelcells. [Copyright &y& Elsevier]

In this work, quaternized poly(arylene ether ketone) (QPAEK)/functionalized TiO 2 (f -TiO 2) composite membranes were fabricated with different f -TiO 2 contents (1, 3, 5, 7, and 9 wt%), and the structure of the materials was characterized by 1H NMR, ATR-FT-IR, XRD, XPS, and FE-SEM. The addition of f -TiO 2 enlarges the ion cluster in the membrane due to enhancing the interaction between the functional groups, and SAXS analysis revealed an extension of the ion domain size with an increase in the filler content (up to 5 wt%). In particular, the composite membrane with 5 wt% f -TiO 2 displayed the highest ion conductivity (74.6 mS cm−1); such a result was attributed to the formation of water traps by the deliquescence of TiO 2 and enhanced interfacial interactions between the pure organic polymers and inorganic nanomaterials. This work proves that a composite membrane with an appropriate f -TiO 2 concentration is a promising candidate for application to anion exchange membranes. [Display omitted] • Anionic organic-inorganic composite membranes are prepared by introducing various amount of f -TiO 2. • The properties of composite membranes are optimized by changing the contents of f -TiO 2. • The prepared membranes show improved mechanical and dimensional stabilities. • The QPAEK/ f -TiO 2 composite membranes demonstrate superior oxidative/alkaline stabilities. [ABSTRACT FROM AUTHOR]

Novel anion conductive nanocomposite membranes with superb hydroxide conductivity and chemical durability in alkaline conditions were prepared by the introduction of quaternary ammonium functionalized graphene oxide (Q-GO) into quaternized poly(arylene ether) (QPAE) random copolymer. Q-GO containing amino silane units, which induce ion cluster formation in the polymer matrix, was synthesized using (3-aminopropyl)triethoxysilane (APTS) and (3-bromopropyl)trimethyl ammonium bromide (PTMA) as the main quaternization reagents. The chemical structures and morphologies of the polymers and inorganic nanofillers were characterized by 1H NMR, FT-IR, FE-SEM, XPS, and SAXS. GO-(APTS- c -PTMA), the so called Q-GO, was used to expand the ion transfer sites and improve the physicochemical stability of the membrane. The electrochemical properties, thermal/mechanical properties, and chemical stabilities of the anion exchange membranes (AEMs) were investigated in accordance with different contents of GO-(APTS- c -PTMA). The π-π bonds between the polymer matrix and the Q-GO resulted in improved dimensional stability and mechanical properties in the composite membrane. The QPAE/GO-(APTS- c -PTMA) 0.7 wt% membrane showed the highest hydroxide conductivity of 114.2 mS cm−1 at 90 °C with an ion exchange capacity of 1.45 mmol g−1, which is 2.07 times higher than the pristine membrane (55.1 mS cm−1 at 90 °C). Furthermore, the single-cell performance of the QPAE/GO-(APTS- c -PTMA) 0.7 wt% as an AEM showed an excellent maximum power density of 135.8 mW cm−2 at 70 °C. Image 1 • Cheap and easy method for crosslinked anion exchange membrane (AEM) preparation for anion exchange membrane fuel cells AEMFC. • The composite AEMs showed highest hydroxide conductivity. • The prepared composite AEMs exhibit long-term chemical stability (>20 days). • The cell was stably operated at 60 °C for 120 h. [ABSTRACT FROM AUTHOR]

A series of anion exchange membranes composed of partially fluorinated poly(arylene ether sulfone)s (PAESs) multiblock copolymers bearing quaternary ammonium groups were synthesized with controlled lengths of the hydrophilic precursor and hydrophobic oligomer via direct polycondensation. The chloromethylation and quaternization proceeded well by optimizing the reaction conditions to improve hydroxide conductivity and physical stability, and the fabricated membranes were very flexible and transparent. Atomic force microscope images of quaternized PAES (QN-PAES) membranes showed excellent hydrophilic/hydrophobic phase separation and distinct ion transition channels. An extended architecture of phase separation was observed by increasing the hydrophilic oligomer length, which resulted in significant improvements in the water uptake, ion exchange capacity, and hydroxide conductivity. Furthermore, the open circuit voltage (OCV) of QN-PAES X10Y23 and X10Y13 was found to be above 0.9 V, and the maximum power density of QN-PAES X10Y13 was 131.7 mW cm−2 at 60 °C under 100% RH. [ABSTRACT FROM AUTHOR]

Sulfonated poly(arylene biphenylether sulfone)-poly(arylene ether) (SPABES-PAE) block copolymers by controlling the molar ratio of SPABES and PAE oligomers were successfully synthesized, and the performances of SPABES-PAE (1:2, 1:1, and 2:1) membranes were compared with Nafion 212. The prepared membranes including fluorinated hydrophobic units were stable against heat, nucleophile attack, and physio-chemical durability during the tests. Moreover, the polymers exhibited better solubility in a variety of solvents. The chemical structure of SPABES-PAEs was investigated by 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC). The membrane of SPABES-PAEs was fabricated by the solution casting method, and the membranes were very flexible and transparent with a thickness of 70–90 μm. The morphology of the membranes was observed using atomic force microscope and the ionic domain size was proved by small angle X-ray scattering (SAXS) measurement. The incorporation of polymers including fluorinated units allowed the membranes to provide unprecedented oxidative and dimensional stabilities, as verified from the results of ex situ durability tests and water uptake capacity, respectively. By the collective efforts, we observed an enhanced water retention capacity, reasonable dimensional stability and high proton conductivity, and the peak power density of the SPABES-PAE (2:1) was 333.29 mW·cm−2 at 60 °C under 100% relative humidity (RH). [ABSTRACT FROM AUTHOR]

In this study, quaternized poly (arylene ether sulfone) (QNPAES) was synthesized using conventional nucleophilic aromatic polycondensation. We then developed a blended membrane composed of sulfonated poly (ether ether ketone) (SPEEK) using facile solution casting. A series of mixed hybrid membranes of SPEEK/QNPAES were prepared by varying the wt% of QNPAES mixed with SPEEK. The results showed that an appropriate amount of QNPAES (i.e., 6 wt%) could significantly improve the mechanical strength, proton conductivity and physicochemical properties of a prepared mixed membrane, as well as the proton exchange membrane fuel cell (PEMFC) performance and durability at relative humidity (RH) of 20%. Specifically, a SPEEK/QNPAES at 6 wt% provides a current output, power output and endurance of 0.431 A cm−2, 0.15 W cm−2 and over 900 h, respectively, at an RH of 20% and 60 °C. These results can be attributed to acid-base ionic crosslinking, which offers effective interfacial compatibility between SPEEK and QNPAES. A PEMFC with SPEEK/QNPAES membranes when used at 20% RH achieved significantly advanced performance and ultra-high, long-term durability compared with those of PEMFCs with bare SPEEK, suggesting that SPEEK/QNPAES membranes can be used as polymer electrolyte membranes. Proton transport of SPEEK/QNPAES acid-base blended membranes for PEFC performance and ultra-high, long-term durability over 900 h. [Display omitted] • QNPAES was synthesized using conventional nucleophilic aromatic polycondensation. • The SPEEK/QNPAES (6 wt%) demonstrated significantly improved proton conductivity. • Acid-base crosslinking offers effective compatibility between SPEEK/QNPAES. • The SPEEK/QNPAES provides maximum current output and power density. • The SPEEK/QNPAES exhibits long-term durability under 20% RH for 900 h. [ABSTRACT FROM AUTHOR]

Summary: In this work, sulfonated diblock copolymers (SDBCs) were prepared by polycondensation of sulfonated poly(ether‐ether‐ketone) (SPEEK) and hydrophobic oligomer, which were combined with sintered anatase titanium oxide (S‐An‐TiO2) to create a hybrid membrane for apply in proton exchange membrane fuel cells (PEMFCs) operating with low relative humidity (RH). Then, a series of composite membranes (SDBC/S‐An‐TiO2) were prepared by varying the wt% of S‐An‐TiO2 blended with SDBC. The results showed that appropriate quantity (ie, 15 wt%) of S‐An‐TiO2 can significantly improve the proton conductivity and physiochemical properties of prepared composite membrane, as well as the PEMFC performance and durability under 20% RH. The 1.5 wt% of SDBC/S‐An‐TiO2 offers high current output, power output, and durability values at 60°C under 20% RH, which are 0.207 A cm−2, 0.074 W cm−2 and over 90 hours, respectively. These results can be attributed to the good interfacial compatibility between S‐An‐TiO2 and SDBC. [ABSTRACT FROM AUTHOR]

We present a volumetric interferometer that has been specially designed to improve the measurement accuracy of the three-dimensional coordinate metrology by reducing excessive Abbe offsets. The interferometer is composed of two main parts; one is a three-dimensionally movable target and the other is a stationary two-dimensional array of photo-detectors. The target made of point diffraction sources emanates two spherical wavefronts, of which interference intensity is monitored by the photo-detectors. Applying phase shifting allows the phases of the photo-detectors to be precisely obtained, and the measured phases are fitted to a geometric model of multilateration so as to determine the xyz-location of the target by minimizing least square errors. A prototype built on a CMM demonstrates that the proposed interferometer is capable of measuring the xyz-coordinates of the probe with a volumetric uncertainty of less than 1.0 μm. [Copyright &y& Elsevier]

A series of novel blended anion exchange membranes (AEMs) were prepared with hyperbranched brominated poly(arylene ether sulfone) (Br-HB-PAES) and linear chloromethylated poly(phenylene oxide) (CM-PPO). The as-prepared blended membranes were fabricated with different weight ratios of Br-HB-PAES to CM-PPO, and the quaternization reaction for introducing the ionic functional group was performed by triethylamine. The Q-PAES/PPO-XY (quaternized-PAES/PPO-XY) blended membranes promoted the ion channel formation as the strong hydrogen bonds interconnecting the two polymers were maintained, and showed an improved hydroxide conductivity with excellent thermal behavior. In particular, the Q-PAES/PPO-55 membrane showed a very high hydroxide ion conductivity (90.9 mS cm−1) compared to the pristine Q-HB-PAES membrane (32.8 mS cm−1), a result supported by the morphology of the membrane as determined by the AFM analysis. In addition, the rigid hyperbranched structure showed a suppressed swelling ratio of 17.9–24.9% despite an excessive water uptake of 33.2–50.3% at 90 °C, and demonstrated a remarkable alkaline stability under 2.0 M KOH conditions over 1000 h. [ABSTRACT FROM AUTHOR]

The development of potential and novel proton exchange membranes (PEMs) is imperative for the further commercialization of PEM fuel cells (PEMFCs). In this work, phosphotungstic acid (PWA) and graphene oxide (GO) were integrated into sulfonated poly(arylene ether) (SPAE) through a solution casting approach to create a potential composite membrane for PEMFC applications. Thermal stability of membranes was observed using thermogravimetric analysis (TGA), and the SPAE/GO/PWA membranes exhibited high thermal stability compared to pristine SPAE membranes, owing to the interaction between SPAEK, GO, and PWA. By using a scanning electron microscope (SEM) and atomic force microscope (AFM), we observed that GO and PWA were evenly distributed throughout the SPAE matrix. The SPAE/GO/PWA composite membrane comprising 0.7 wt% GO and 36 wt% PWA exhibited a maximum proton conductivity of 186.3 mS cm−1 at 90 °C under 100% relative humidity (RH). As a result, SPAE/GO/PWA composite membrane exhibited 193.3 mW cm−2 of the maximum power density at 70 °C under 100% RH in PEMFCs. [ABSTRACT FROM AUTHOR]

We designed and synthesized a series of sulfonated poly(arylene ether sulfone) (SPES) with different hydrophilic or hydrophobic oligomer ratios using poly-condensation strategy. Afterward, we fabricated the corresponding membranes via a solution-casting approach. We verified the SPES membrane chemical structure using nuclear magnetic resonance (1H NMR) and confirmed the resulting oligomer ratio. Field-emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM) results revealed that we effectively attained phase separation of the SPES membrane along with an increased hydrophilic oligomer ratio. Thermal stability, glass transition temperature (Tg) and membrane elongation increased with the ratio of hydrophilic oligomers. SPES membranes with higher hydrophilic oligomer ratios exhibited superior water uptake, ion-exchange capacity, contact angle and water sorption, while retaining reasonable swelling degree. The proton conductivity results showed that SPES containing higher amounts of hydrophilic oligomers provided a 74.7 mS cm−1 proton conductivity at 90 °C, which is better than other SPES membranes, but slightly lower than that of Nafion-117 membrane. When integrating SPES membranes with proton-exchange membrane fuel cells (PEMFCs) at 60 °C and 80% relative humidity (RH), the PEMFC power density exhibited a similar increment-pattern like proton conductivity pattern. [ABSTRACT FROM AUTHOR]