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Hydrophobic side chain grafted poly(fluorenyl-co-aryl piperidinium) ionomers simultaneously possess outstanding peak power density of 2.6 W cm−2 at 80 °C along with durable in situ stability of 0.4 mV h−1 voltage decay rate under 0.6 A cm−2 at 70 °C.

Anion-exchange-membrane fuel cells (AEMFCs) are a cost-effective alternative to proton-exchange-membrane fuel cells (PEMFCs). The development of high-performance and durable AEMFCs requires highly conductive and robust anion-exchange membranes (AEMs). However, AEMs generally exhibit a trade-off between conductivity and dimensional stability. Here, a fluorination strategy to create a phase-separated morphological structure in poly(aryl piperidinium) AEMs is reported. The highly hydrophobic perfluoroalkyl side chains augment phase separation to construct interconnected hydrophilic channels for anion transport. As a result, these fluorinated PAP (FPAP) AEMs simultaneously possess high conductivity (>150 mS cm(-1) at 80 degrees C) and high dimensional stability (swelling ratio 80 MPa and elongation at break >40%) and chemical stability (>2000 h in 3 m KOH at 80 degrees C). AEMFCs with a non-precious Co-Mn spinel cathode using the present FPAP AEMs achieve an outstanding peak power density of 1.31 W cm(-2). The AEMs remain stable over 500 h of fuel cell operation at a constant current density of 0.2 A cm(-2).

Polyethylene reinforced poly(aryl-co-aryl piperidinium) based membranes possess outstanding mechanical properties (tensile strength: 114 MPa, elongation at break: 159%) along with a fuel cell performance of 1.75 W cm−2 at 80 °C.

Di-piperidinium crosslinked poly(fluorenyl-co-terphenyl piperidinium) membranes displayed outstanding mechanical strength (∼90 MPa) and durability along with high power density of 2.50 W cm−2 in alkaline exchange membrane fuel cells.

The alkaline stability of N-heterocyclic ammonium (NHA) groups is a critical topic in anion-exchange membranes (AEMs) and AEM fuel cells (AEMFCs). Here, we report a systematic study on the alkaline stability of 24 representative NHA groups at different hydration numbers (λ) at 80 °C. The results elucidate that γ-substituted NHAs containing electron-donating groups display superior alkaline stability, while electron-withdrawing substituents are detrimental to durable NHAs. Density-functional-theory calculations and experimental results suggest that nucleophilic substitution is the dominant degradation pathway in NHAs, while Hofmann elimination is the primary degradation pathway for NHA-based AEMs. Different degradation pathways determine the alkaline stability of NHAs or NHA-based AEMs. AEMFC durability (from 1 A cm-2 to 3 A cm-2 ) suggests that NHA-based AEMs are mainly subjected to Hofmann elimination under 1 A cm-2 current density for 1000 h, providing insights into the relationship between current density, λ value, and durability of NHA-based AEMs.

A key to sustainable management of hypersaline organic-rich wastewaters is to precisely fractionate organic components and inorganic salts (NaCl) as individual resources. Conventional nanofiltration and electrodialysis processes suffer from membrane fouling and compromise the fractionation efficacy. Here, we develop a thin-film composite nanoporous membrane (NPM) via co-deposition of dopamine and polyethyleneimine as a highly anion-conducting membrane (ACM). Experimental results and molecular dynamics simulations show that co-deposition of dopamine and polyethyleneimine effectively tailors the membrane surface properties, intensifying the charge shielding effect and enabling ultrafast anion transfer for highly efficient electrodialysis. The resulting NPM exhibits unprecedented electrodialytic fractionation of organics and NaCl (> 99.3% desalination efficiency; >99.1% organics recovery) with negligible membrane fouling, dramatically outperforming state-of-the-art anion exchange membranes. Our study sheds light on facile design of high-performance ACMs and associated new mass transport mechanisms in electrodialytic separation, paving the way for sustainable management of complex waste streams.

Gas-separation membranes are a critical industrial component for a low-carbon and energy-efficient future. As a result, many researchers have been testing membrane materials over the past several decades. Unfortunately, almost all membrane-based testing systems are home-built, and there are no widely accepted material standards or testing protocols in the literature, making it challenging to accurately compare experimental results. In this multi-lab study, ten independent laboratories collected high-pressure pure-gas permeation data for H2, O2, CH4, and N2 in commercial polysulfone (PSf) films. Equipment information, testing procedures, and permeation data from all labs were collected to provide (1) accepted H2, O2, CH4, and N2 permeability values at 35 °C in PSf as a reference standard, (2) statistical analysis of lab-to-lab uncertainties in evaluating permeability, and (3) a list of best practices for sample preparation, equipment set-up, and permeation testing using constant-volume variable-pressure apparatuses. Results summarized in this work provide a reference standard and recommended testing protocols for pure-gas testing of membrane materials.

Aryl‐ether‐free anion‐exchange ionomers (AEIs) and membranes (AEMs) have become an important benchmark to address the insufficient durability and power‐density issues associated with AEM fuel cells (AEMFCs). Here, we present aliphatic chain‐containing poly(diphenyl‐terphenyl piperidinium) (PDTP) copolymers to reduce the phenyl content and adsorption of AEIs and to increase the mechanical properties of AEMs. Specifically, PDTP AEMs possess excellent mechanical properties (storage modulus>1800 MPa, tensile strength>70 MPa), H2 fuel‐barrier properties (7.6 A cm−2 current density) and 1.38 W cm−2 at 80 °C in H2/O2 and H2/air, respectively, along with a specific power (PPD/catalyst loading) over 8 W mg−1, which is the highest record for Pt‐based AEMFCs so far., Poly(alkyl‐terphenyl piperidinium) membranes and ionomers display outstanding hydrogen‐barrier properties and mechanical properties as well as excellent hydroxide‐ion conductivity that results in an excellent power density of 2.58 W cm−2 and 1.38 W cm−2 at 80 °C in H2/O2 and H2/air, respectively, along with a new, outstanding specific power in alkaline‐exchange‐membrane fuel cells.

Improving the chemical resistance of membranes without sacrificing their molecular sieving performance is highly challenging. Herein, a novel scalable methodology was developed for fabricating solvent-resistant nanofiltration membranes based on metal–polymer coordination (MPC) through a facile yet highly effective method. The controlled deposition of copper(I) iodide enabled the fine-tuning of the molecular sieving performance of MPC membranes by altering both their chemistry and morphology. Spectroscopic and morphological analyses were conducted to elucidate the microscopic and macroscopic properties of the membranes. The formation of coordination bonds between the metal and polybenzimidazole chains protected the membranes from dissolving in harsh organic solvents. Additionally, computational modeling was performed to reveal the stabilization energy and fractional free volume (FFV). Our work opens more sustainable avenues for robust membrane fabrication without conventional crosslinking, which requires reactive chemicals.

Polymer membranes have attracted interest in many areas, such as desalination, water treatment, gas separation, and energy storage and generation. Membrane fabrication requires large amounts of solvents for polymer dissolution. These solvents often show toxicity and need to be replaced by greener solvents to avoid adverse effects on human health and increase sustainability of the production processes. The need to use non-toxic compounds is increasing with the strong growth of the global membrane market. This review focuses on green solvents and green materials to prepare polymer-based membranes for the steadily increasing range of applications. Membrane fabrication techniques, choice of emerging green solvents, economic evaluation, and application areas will be comprehensively and critically reviewed. This review provides important selection guidelines for greener solvents for chemists, chemical engineers, and material scientists, focusing on organic chemicals and polymer processing. Furthermore, a simple cost analysis for a typical green solvent is provided, and its impact on the membrane fabrication cost is discussed. This journal is

Low-cost anion exchange membrane (AEM) water electrolyzers (AEMWEs) are a new technology for the production of high-purity hydrogen; however, their current density and durability are far lower than those of proton exchange membrane water electrolyzers (PEMWEs). Here, we report poly(fluorenyl-co-aryl piperidinium) (PFAP)-based anhydrous cathode AEMWEs that exceed the state-of-the-art PEMWEs with respect to current density. In addition to a rational electrode design, PFAP-based AEMs with a high water diffusivity and ion conductivity are crucial for high-performance AEMWEs. Using platinum-group-metal (PGM) catalysts, the present AEMWEs achieved a new record current density of 7.68 A cm−2 at 2.0 V with a 1 M KOH anode, which surpasses that of state-of-the-art PEMWEs (6 A cm−2 at 2.0 V). PGM-free AEMWEs displayed an excellent current density of 1.62 A cm−2 at 2.0 V. Importantly, PGM and PGM-free AEMWEs operated stably under a 0.5 A cm−2 current density at 60 °C for more than 1000 h. This work sheds light on current high-performance AEMWEs.

Though membrane separation has been an efficient and energy-saving technique for dealing with wasted mixed chemical matter, the concomitant environmental pollution has become a big issue in the dev...

Anion-exchange membrane fuel cells (AEMFCs) are a promising, next-generation fuel cell technology. AEMFCs require highly conductive and robust anion-exchange membranes (AEMs), which are challenging to develop due to the tradeoff between conductivity and water uptake. Here we report a method to prepare high-molecular-weight branched poly(aryl piperidinium) AEMs. We show that branching reduces water uptake, leading to improved dimensional stability. The optimized membrane, b-PTP-2.5, exhibits simultaneously high OH

Description, Cascaded microporosity localized on membrane surfaces markedly improved selective transport of small molecules., In membrane-based separation, molecular size differences relative to membrane pore sizes govern mass flux and separation efficiency. In applications requiring complex molecular differentiation, such as in natural gas processing, cascaded pore size distributions in membranes allow different permeate molecules to be separated without a reduction in throughput. Here, we report the decoration of microporous polymer membrane surfaces with molecular fluorine. Molecular fluorine penetrates through the microporous interface and reacts with rigid polymeric backbones, resulting in membrane micropores with multimodal pore size distributions. The fluorine acts as angstrom-scale apertures that can be controlled for molecular transport. We achieved a highly effective gas separation performance in several industrially relevant hollow-fibrous modular platform with stable responses over 1 year.

Two‐dimensional nanosheets have shown great potential for separation applications because of their exceptional molecular transport properties. Nanosheet materials such as graphene oxides, metal–organic frameworks, and covalent organic frameworks display unique, precise, and fast molecular transport through nanopores and/or nanochannels. However, the dimensional instability of nanosheets in harsh environments diminishes the membrane performance and hinders their long‐term operation in various applications such as gas separation, water desalination, and ion separation. Recent progress in nanosheet membranes has included modification by crosslinking and functionalization that has improved the stability of the membranes, their separation functionality, and the scalability of membrane formation while the membranes’ excellent molecular transport properties are retained. These improvements have enhanced the potential of nanosheet membranes in practical applications such as separation processes., Modification of nanosheet membranes by crosslinking and functionalization has improved their stability, their separation functionality, and the scalability of membrane production while retaining the membranes’ excellent molecular transport properties. These improvements have enhanced the potential of nanosheet membranes in practical applications such as separation processes.

Thermally Rearranged (TR) polymers and Mixed Matrix Membranes (MMMs) are two effective approaches used to advance the performance of gas separation membranes. Conversion of thermally activated groups in TR membranes result in hourglass-shaped cavities and unusually high permselectivity, whereas the inclusion of nanoparticles with engineered pore volume, window size and/or surface chemistry in MMMs can add fast and selective pathways for gas transport. In this study, we explored the effects of combining these two approaches by adding ultra-porous and highly thermostable PAF-1 nanoparticles into the TR-able polymer, 6FDA-HAB5DAM5 (DAM). Gas separation performances of TR-MMMs were evaluated by comparison with the pure polymer and another TR-MMM bearing an already thermally-treated PAF-1 additive (cPAF). While both additives enhanced gas transport, only PAF-1 stabilized the TR conversion reaction and improved the TR-MMM's material properties. Minor variations in cPAF surface changed the TR-MMM interfacial interactions as well as other properties crucial to the application of advanced membrane materials, namely aging, plasticization, and mechanical stability. By combining thermal rearrangement process with PAF-1, TR-MMM demonstrated a 55-fold increase in CO2 gas permeability (37-fold for H2) at similar gas selectivities, but without the handling issues observed for the pure TR polymer membrane.

To develop new cost-effective and high performance ion exchange membranes (IEMs) for redox flow battery applications, poly(arylene ether sulfone) random copolymer membranes (BPSHs) with surface nano-crack coatings (P-BPSH) were prepared using a hydrophobic atmospheric plasma treatment. The effect of the nano-cracks on the membranes' ion transport properties and the performance of the vanadium redox flow batteries (VRFBs) were evaluated to better understand the feasibility of using this technique in membrane ionic selectivity. The ion-selective nano-crack surface significantly improved the proton selectivity, from 32.95 to 74.20, over vanadium (VO2+) ions. Consequently, the VRFB cell assembled using a P-BPSH-60 membrane showed higher coulombic and energy efficiencies compared to a VRFB with a pristine BPSH-60 membrane. The energy efficiency of the P-BPSH-60 membrane (85.37%) is comparable to that of a Nafion® 117 membrane (85.11%). The improved battery performance demonstrated that the surface nano-crack coating layer effectively blocked the transport of vanadium ions through the IEM without distinct reduction of the proton conductivity. The results suggest a promising strategy to enhance membrane proton selectivity over vanadium ions.

Polycrystalline zeolitic imidazolate framework ZIF-8 membranes have shown great potential for energy-efficient propylene/propane separation. Their large-scale applications are, however, hampered by...

Mixed matrix membranes (MMMs) with a thermally rearranged (TR) polymer and zeolitic imidazolate framework-8 (ZIF-8) were prepared in this study. ZIF-8 contributed to not only enhancing gas permeability, but also promoting thermal conversion of TR polymer membranes. As a result, TR ZIF-8 MMMs can be prepared at lower temperatures compared to the original TR polymers. The thermal rearrangement process also increased gas separation properties as it contributes to a tunable cavity size and hour-glass shape cavity distributions. Moreover, interfacial voids between the polymer phase and ZIF crystals which usually occur in most MMMs disappeared during thermal rearrangement of the TR polymer. As a result, the TR ZIF-8 MMMs showed excellent hydrogen separation properties with a H2 permeability of 1,206 Barrer, H2/N2 selectivity of 22.3, and H2/CH4 selectivity of 25.7.

Each component of a gas mixture affects the permeation of the other gases. This mutual influence was systematically investigated for binary gas mixtures that included CO2, N-2, CH4, H-2, and CO permeating through thermally rearranged poly(benzoxazole-co-imide) (TR-PBOI) membranes. The mixed gas permeation was measured at 35 degrees C at up to 5 bar of feed pressure. Sorption isotherms of binary mixtures were calculated using the Grand Canonical Monte Carlo approach for quantifying the sorption contribution to the permeation. The diffusivity contribution was estimated by using the permeability value. How and how much CO2 (the most soluble gas) and H-2 (the fastest diffusing gas among the gas species tested) affect each other's permeation as well as the permeation of the other gases were specifically addressed, including a discussion based on sorption and diffusion contributions. The permeance of CO2 and H-2 remained unchanged, whereas the permeance of the other gases was reduced by the presence of CO2 or increased by the presence of H-2.

Aliphatic/alicyclic (Al)-containing polyimides (PIs), including fully-Al-PIs and partially-Al-PIs, are widely employed in electric, electronics, optical materials, and other advanced material fields. Examples include high speed multiplayer printed wiring boards, alignment films for liquid-crystal displays, fuel cells, batteries, gas separation membranes, pervaporation membranes, biomedical applications, and composites/hybrid materials. In the past decades, research has focused on the synthesis and molecular design of fully-Al-PIs and partially-Al-PIs. However, the effects of aliphatic/alicyclic segments on the performance of fully-Al-PIs and partially-Al-PIs and their potential applications are not clear. Therefore, an overall clarification of aliphatic/alicyclic-containing monomers, the effects of aliphatic/alicyclic segments on PI performance, as well as recent applications for advanced technology are important topics for further study. This review systematically summarizes the available aliphatic/alicyclic monomers and clarifies the influence of aliphatic/alicyclic-containing segments in chain backbones on the morphology and properties of the resulting PIs. Further, the use of PIs in applications for advanced materials is discussed, along with the outlook for the future of aliphatic/alicyclic-containing polyimides and their advanced applications.

The membrane market has grown rapidly over the past several decades, supported by continuous improvements in membrane performance, module and process design, and fouling control. However, such growth will be unsustainable with current membrane fabrication methods that employ significant amounts of toxic solvents (e.g., N-methylpyrrolidone, dimethylacetamide, and dimethylformamide), thereby producing billions of liters of contaminated wastewater each year. A possible solution is to identify greener alternatives with appropriate properties that are compatible with conventional polymers. In this work, we employed a novel green solvent, Rhodiasolv PolarClean®, that is less toxic than current solvents and eco-friendly, while exhibiting the necessary properties to be employed as a solvent for membrane preparation via the nonsolvent-induced phase separation (NIPS) method. Rhodiasolv PolarClean® has been successfully applied to membrane preparation for water desalination and reclamation by ultrafiltration (UF) and nanofiltration (NF) with conventional polymers, including polysulfone (PSF), polyethersulfone (PES), and cellulose acetate (CA). The UF membranes prepared from PES/Pluronic F127 and PSF/polyvinylpyrrolidone exhibited pure water permeabilities greater than 314.5 ± 57.8 L m−2 h−1 bar−1 and tensile strength 3.78 ± 0.12 MPa with BSA rejection of 98.1 ± 0.4%. Cellulose acetate membrane used for NF applications demonstrated pure water permeability of 1.5 ± 0.25 L m−2 h−1 bar−1 with NaCl and MgCl2 rejection of 85.1 ± 5.7% and 93.2 ± 4.7%, respectively. The performance of the prepared membranes was competitive with current state-of-the-art membranes across all applications, indicating immediate applicability to improving the sustainability of membrane fabrication processes.

Since thermally rearranged (TR) polymers were known as high gas permeable and processable materials, fabricating high performance hollow fiber (HF) membranes have been tried using them. However, an unexpected drawback emerged which is the gas productivity loss by thermal densification of skin layers during thermal treatment above their glass transition temperature (Tg). In this work, we used a recently reported crosslinked-TR (XTR) polybenzoxazole to develop a new class of high-flux TR hollow fibers by directly exploiting the thermal densification phenomenon. The TR temperature range (320–460 °C) and Tg (394 °C) were determined by thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The chain rigidity of the XTR polymer increased during an isotherm treatment at its Tg, suggesting a restricted densification. Surprisingly, the undesired pinhole-defects (pore diameter 400 °C), forming an ultrathin defect-free skin layer on thermally-densified XTR hollow fiber membranes. The pore-healed XTR hollow fibers exhibited an outstanding CO2 permeance of ~2300 GPU and a CO2/N2 selectivity of 17.4 with a skin thickness of 103 nm.

Artificial lung (AL) membranes are used for blood oxygenation for patients undergoing open-heart surgery or acute lung failures. Current AL technology employs polypropylene and polymethylpentene membranes. Although effective, these membranes suffer from low biocompatibility, leading to undesired blood coagulation and hemolysis over a long term. In this work, we propose a new generation of AL membranes based on amphiphobic fluoropolymers. We employed poly(vinylidene-co-hexafluoropropylene), or PVDF-co-HFP, to fabricate macrovoid-free membranes with an optimal pore size range of 30-50 nm. The phase inversion behavior of PVDF-co-HFP was investigated in detail for structural optimization. To improve the wetting stability of the membranes, the fabricated membranes were coated using Hyflon AD60X, a type of fluoropolymer with an extremely low surface energy. Hyflon-coated materials displayed very low protein adsorption and a high contact angle for both water and blood. In the hydrophobic spectrum, the data showed an inverse relationship between the surface free energy and protein adsorption, suggesting an appropriate direction with respect to biocompatibility for AL research. The blood oxygenation performance was assessed using animal sheep blood, and the fabricated fluoropolymer membranes showed competitive performance to that of commercial polyolefin membranes without any detectable hemolysis. The data also confirmed that the bottleneck in the blood oxygenation performance was not the membrane permeance but rather the rate of mass transfer in the blood phase, highlighting the importance of efficient module design.

Producción Científica, Mixed matrix membranes (MMMs) have been obtained by blending an aromatic ortho-hydroxypolyimide (PIOH) or an ortho-acetylpolyimide (PIOAc) with different loading amounts (15 and 30 wt %) of a microporous polymer network (PPN), which was obtained from the reaction of triptycene and isatin. The excellent thermal resistance of the PPN (above 500 °C) allowed it to be used as a filler to successfully prepare thermally rearranged polybenzoxazole (TR-PBO)-MMMs obtained from the thermal treatment of the above MMMs. Moreover, PPN showed relatively good compatibility with the polyimide matrix, which improved the TR-PBO formation. The gas separation performances of these MMMs before and after the thermal process were studied for five representative gases (He, O2, N2, CO2, and CH4). For the MMMs derived from ortho-functional polyimides, the gas permeability considerably increased for all of the gases, whereas the selectivity for gas pairs, such as CO2/N2 and CO2/CH4, remained similar. Thus, the selectivity-permeability performance of PIOH- and PIOAc-MMMs containing 30 wt % of PPN (PIOH30 and PIOAc30) surpassed the 1991 Robeson limit for the CO2/CH4 gas pair. In the case of TR-PBO-MMMs (TROH and TROAc-MMMs), the thermal rearrangement process led to an increase in the gas permeability, showing values much better than those observed for the TR-PBO material employed as a MMM matrix. The selectivity values were a little bit lower than the pristine TR-PBO membranes. The CO2 permeability of TROAc30 was 1036 barrer with a CO2/CH4 selectivity of 28, surpassing the 2008 Robeson limit., Agencia Estatal de Investigación - Fondo Europeo de Desarrollo Regional - Unión Europea (projects PID2019-109403RB-C22, CTQ2017-89217-P and PID2019-109403RB-C21), Junta de Castilla y León (project VA224P20), Ministerio de Ciencia, Innovación y Universidades - ICT (project RTI2018-096652-B-I00), Ministry of Trade, Industry & Energy of South Korea.(project 20202020800330)

Solder paste is the main interconnect material to use between FBGA type packages and main boards. It is consisted of different types of solder powers (in case of type 3 size is 25∼45um) and flux. Many paste parameters, such as paste composition, printing stencil aperture and reflowing profile, influence the printing performance and the reflow process of solder pastes. Flux in solder paste is classified into mainly water-soluable and no-clean flux depending on the applications. No-clean flux contained solder paste has been used in most of applications such as module, SSD etc. But, water-soluable flux contained solder paste is required in SiP module applications to prevent any possible corrosion failure due to flux residue in underfilled module. However, water-soluable flux is very sensitive by humidity in storage condition. Activation and viscosity of flux can be degraded by uncontrolled environment and caused unexpected rotation to resulted in poor solder joint self align. In general, the rheology of solder paste is complicated and affect the shape of solder joint depending on ratio of moisture absoption. If the mixture of solder paste absorb the moisture, the solder paste could be easily slumped and package component is slipped or rotated during the reflow process, result in poor solder joint quality such as non-wet. There are several methods to detect the poor solder joint quality after SMT, such as X-ray and Optical Inspection. The benefits of X-ray inspection are broad in scope due to the ability of X-rays to see through packages including. But X-ray method is restricted to used in massive production due to its poor detection resolution and low efficiency of analytical time. Especially, the poor self-align quality like non-wet joint could not be easily detected by X-ray only after SMT, so the failure samples could be outflow to customers. The main purpose of this study was to investigate effective monitoring methods for replacing sampling X-ray measurement. The existing automatic optical inspection (AOI) equipment can be used to check out the defect of the electronic products, such as solder bridging, non-wet and so on. In this paper, the solder joint self-align trend (amount of rotation) was calculated by M-AOI (Mounting-AOI of package before reflow) and S-AOI (Solidifying-AOI after reflow) data. The trends of M-AOI and S-AOI was compared with non-wet failure rate at final test and X-ray inspection result for relevant properties of solder paste such as viscosity, thixotropy, acidity and so on. AOI data shows well-matched trend with amount of rotation of package and non-wet failure rate of solder joints with regard to floor time of solder paste. As a result, new monitoring method using AOI is proposed and confirm usefulness to replace the sampling X-ray measurement as massively useful tool to check the joint quality after reflow process, and also will be used to control the moisture level of solder paste to ensure the proper rheology for SMT assembly.

Widespread use of biofuels is inhibited by the significant energy burden of recovering fuel products from aqueous fermentation systems. Here, we describe a membrane-based extraction (perstraction) system for the recovery of fuel-grade biobutanol from fermentation broths which can extract n-butanol with high purity (>99.5%) while using less than 25% of the energy of current technology options. This is achieved by combining a spray-coated thin-film composite membrane with 2-ethyl-1-hexanol as an extractant. The membrane successfully protects the micro-organisms from the extractant, which, although ideal in other respects, is a metabolic inhibitor. In contrast to water, the extractant does not form a heterogeneous azeotrope with n-butanol, and the overall energy consumption of for n-butanol production is 3.9 MJ kg−1, substantially less than other recovery processes (17.0–29.4 MJ kg−1). By (a) extracting n-butanol from the fermentation broth without a phase change, (b) breaking the heterogeneous azeotrope relationship (less energy consumption for distillation), and (c) utilizing a small volume ratio of extractant : fermentation broth (1 : 100, v/v), the need for high energy intensity processes such as pervaporation, gas stripping or liquid–liquid extraction is avoided. The application of this perstraction system to continuous production of a range of higher alcohols is explored and shown to be highly favourable.

Low-cost anion exchange membrane fuel cells have been investigated as a promising alternative to proton exchange membrane fuel cells for the last decade. The major barriers to the viability of anion exchange membrane fuel cells are their unsatisfactory key components—anion exchange ionomers and membranes. Here, we present a series of durable poly(fluorenyl aryl piperidinium) ionomers and membranes where the membranes possess high OH− conductivity of 208 mS cm−1 at 80 °C, low H2 permeability, excellent mechanical properties (84.5 MPa TS), and 2000 h ex-situ durability in 1 M NaOH at 80 °C, while the ionomers have high water vapor permeability and low phenyl adsorption. Based on our rational design of poly(fluorenyl aryl piperidinium) membranes and ionomers, we demonstrate alkaline fuel cell performances of 2.34 W cm−2 in H2-O2 and 1.25 W cm−2 in H2-air (CO2-free) at 80 °C. The present cells can be operated stably under a 0.2 A cm−2 current density for ~200 h., Developing high-performance anion exchange membranes and ionomers is crucial for low-cost alkaline fuel cells. Here, the authors explore rigid and high ion conductive poly(fluorenyl aryl piperidinium) copolymers, extending their applications to anion exchange membrane fuel cells.

It is of great interest to form polycrystalline metal–organic framework (MOF) thin films on polymer substrates or MOF/polymer composites for their practical applications in sensing and separation. It is, however, quite challenging to fabricate high-quality MOF thin films on polymer substrates or MOF/polymer composites in a facile manner. Herein, we report a simple in situ method to fabricate high-quality zeolitic-imidazolate framework ZIF-8 thin films supported on polymers as well as ZIF-8/polymer composites by doping polymers with zinc ions followed by solvothermal treatment in a linker solution. The effects of key synthesis parameters on the microstructures of ZIF-8 thin films and composites were systematically studied. Formation of ZIF-8 crystals was confirmed using ATR-FTIR, EDX, XRD, SEM, and TEM. While continuous ZIF-8 films were observed on the substrate surfaces, it was revealed that ZIF-8 particles formed inside the substrates as well (i.e., ZIF-8/polymer mixed-matrix layers). The thicknesses of the mixed-matrix layers were demonstrated to be controllable by varying the kinetics of alkali hydrolysis. The method was applied to a family of ZIFs (i.e., ZIF-8 and ZIF-67) and mixed-metal ZIF-8 analogues, proving its versatility. Finally ultra-thin well-intergrown ZIF-8 membranes were prepared by secondarily growing ZIF-8 films on Matrimid® hollow fibers, showing promising propylene/propane separation performances.

In this report, we introduced spirobiindane group to poly(arylene ether sulfone) (PES) to build the structure of polymers with intrinsic microporosity (PIMs). A novel PESs (QOH-SBIs), which have spirobiindane and tetra(quaternary ammonium) hydroxide pendant moieties, were synthesized for anion-conducting binder material in membrane electrode assembly (MEA) of solid alkaline exchange membrane fuel cell (SAEMFC). The time-lag method was used to check the high gas permeability of the polymers. The high permeability is due to the micro-pores at the molecular level that is formed by the difference in chain thicknesses between two alternating units, thick spirobiindane group and thin arylene ether sulfone group. QOH-SBIs shows a semi-rigid chain conformation in a solution. The inter-chain spacing and chain conformation were measured with wide angle X-ray diffraction (WAXD) and small angle neutron scattering (SANS), respectively. High gas permeability directly affected the performance of SAEMFC. The MEA with spirobiindane-modified PES shows much higher maximum power density than that of spirobiindane-free PESs.