Microphase-separated Structure Research Articles

Poly(isatin biphenylene) anion exchange membranes based on functionalization of long side chain N-spirocyclic

N-spirocyclic cations have high alkali resistance stability, but their poor mobility hinders the aggregation of cationic groups, which makes it difficult to form a good microphase-separated structure for OH− ion transport. In this work, two kinds of bicationic N-spirocyclic cations containing spacer side chains (BM-DSU and BM-DSD) were designed and synthesized, and a series of poly(isatin biphenylene) anion exchange membranes containing bicationic N-spirocyclic side chains were prepared by grafting different ratios of N-spirocyclic cations onto the poly(isatin biphenylene) polymer backbone. The bicationic N-spirocyclic quaternary ammonium salts containing spacer side chains increased the migration rate of the cationic groups and constructed a more continuous ion transport channel. The OH− ionic conductivities of BM-DSD-PIB-40 and BM-DSU-PIB-40 were 67.8 mS cm−1 and 63.4 mS cm−1 at 80 °C. After soaking at 80 °C in 1 M NaOH for 730 h, the residual conductivities of BM-DSD-PIB-30 and BM-DSU-PIB-30 were 73.19 % and 78.02 %, respectively.

Ultra-Tough Dynamic Supramolecular Ion-Conducting Elastomer Induced Uniform Li+ Transport and Stabilizes Interphase Ensures Dendrite-Free Lithium Metal Anodes.

Artificial polymer solid electrolyte interphases (SEIs) with microphase-separated structures provide promising solutions to the inhomogeneity and cracking issues of natural SEIs in lithium metal batteries (LMBs). However, achieving homogeneous ionic conductivity, excellent mechanical properties, and superior interfacial stability remains challenging due to interference from hard-phase domains in ion transport and solid-solid interface issues with lithium metal. Herein, we present a dynamic supramolecular ion-conducting poly (urethane-urea) interphase (DSIPI) that achieves these three properties through modulating the hard-phase domains and constructing a composite SEI in situ. The soft-phase polytetrahydrofuran backbone, featuring loose Li+-O coordinating interactions, ensures uniform Li+ transport. Concurrently, sextuple hydrogen bonds in the hard phase dissipate strain energy through sequential bond cleavage, thereby imparting exceptional mechanical properties. Moreover, enriched bis (trifluoromethanesulfonyl) imide anion (TFSI-) in DSIPI promotes the in situ formation of a stable polymer-inorganic composite SEI during cycling. Consequently, the DSIPI-protected lithium anode (DSIPI@Li) enables symmetric cells with exceptional cyclability exceeding 4,000 hours at an ultra-high current density of 20 mA cm-2, thereby demonstrating excellent cycling stability. Furthermore, DSIPI@Li facilitates stable operation of the pouch cells under the constraints of a high-loading LiNi0.8Co0.1Mn0.1O2 cathode and low negative/positive capacity (N/P) ratio. This work presents a powerful strategy for designing artificial SEIs and high-performance LMBs.

Liquid Crystal Promoted Self-Assembly of Statistical Copolymers into Diverse Nanostructures with Precise Dimensions.

In both natural and synthetic systems, the segregation of multicomponent entities is vital for regulating functions and the ultimate usage of materials. To accomplish the desired properties via nanosegregation or microphase separation, great effort is usually demanded in the synthesis. For example, microphase-separated block copolymers rely on the delicate controlled/living polymerization of different monomers in sequence. Here, we demonstrate that a facile one-pot copolymerization can generate statistical side-chain copolymers exhibiting well-defined and diverse nanostructures. Two hemiphasmidic (or wedge-shaped) cyclooctene monomers were designed, differing in the peripheral tails of the wedges (dodecyl vs. tetraethylene glycol), with lengths of ca. 1 nm. When combining the two monomers together, the statistical copolymers can show columnar liquid crystal (LC) phase and microphase-separated structures of the two monomers, including sphere, cylinder, double gyroid, and lamella. To the best of our knowledge, this is the first time the gyroid phase has been achieved in statistical copolymers. We further demonstrate that changing the side chains to calamitic (or rod-like) mesogens or the backbone to less flexible polynorbornene, the statistical copolymers can also undergo microphase separation of the side chains. The intrinsic self-assembly scheme of statistical copolymers with mesogenic side chains, which are chemically accurate, affords the resultant nanostructures with precise periodicities at the 10- or sub-10-nm scale. Given the small chemical difference between the side-chain tails, microphase separation is promoted by the anisotropic packing of mesogens. It is validated that the statistical side-chain LC copolymers can be a versatile platform for creating nanostructured materials with tailored functionalities.

Preparation and melt-spun applications of PA6-based Poly(Amide-Ether) copolymers phase change fibers with passive temperature management

Phase change fiber, as an intelligent fiber material used in passive thermal management, can balance the temperature of the microenvironment near human skin. However, the traditional blending method makes phase change material prone to leakage during the processing and applications. Herein, this work introduces the phase change material PTMEG into the polyamide 6 (PA6) chain through melt polymerization to prepare a series of PA6-based poly(amide-ether) copolymers. Copolymers exhibit an obvious microphase separation structure, with the PA6 segments and the PTMEG segments can form independent crystalline and amorphous regions. PTMEG in copolymers through polymerization method exhibits better thermal stability compared with the blended way, which effectively solves the leakage problem of phase change materials. The copolymers can be directly melt-spun (1500 m/min) to prepare PA6-based phase change fibers. The fiber can maintain excellent mechanical properties (breaking strength of 2.12 cN/dtex). Meanwhile, the crystallization enthalpy and melting enthalpy of the PTMEG in the fiber are 10.59 J/g and 12.44 J/g, respectively. The thermal management time of the fiber in the hot environment is 349 s, and the maximum temperature difference is lower 5.6 ℃ from the PA6 fiber. In addition, the exothermic duration in a cold environment is 536 s, and the maximum temperature difference is higher 1.1 °C from the PA6 fiber. Meanwhile, the thermal enthalpy of the fiber remained stable (fluctuation within 2 %) after 20th thermal cycles, and the loss rate is less than 2 % after washing at 25 ℃, 50 ℃ and 90 ℃. The fiber exhibits good thermal stability, water washability and cyclic stability. Preparation of high enthalpy polymers directly by copolymerization will provide new ideas for phase change fibers for apparel.

Alkaline stable cross-linked anion exchange membrane based on steric hindrance effect and microphase-separated structure for water electrolyzer

This study focuses on the development of cross-linked anion exchange membranes (AEMs) based on polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS), known for its ether free backbone and excellent chemical stability. The cross-linked SEBS (X-SEBS-BC) membranes were synthesized using an eco-friendly method with SnCl4 under mild conditions. A cross-linking agent, 1,4-diazbicyclo[2.2.2]octane (DABCO), was employed to enhance ion conducting channels and improve alkaline stability by preventing degradation. The resulting membranes exhibited low swelling, high conductivity, and significant chemical stability in alkaline environments. This is achieved through the rigid cage-like structure of DABCO, which hinders syn-periplanar conformational changes and protects against the degradation of SN2 and ylide reactions. Their well-defined microphase-separated morphology, observed through TEM, supports effective ion transport. Notably, the X-SEBS-BC-0.81 membrane showed excellent alkaline stability, with minimal degradation in 3 M KOH over 30 days at 30 °C and 3.3% degradation in 1 M KOH over 600 hours at 50 °C. In water electrolysis tests, this membrane demonstrated superior performance (0.95 Acm−2 at 2.0 V), surpassing the commercial FAA-3-50 membrane by 82%. These findings highlight the potential of X-SEBS BC membranes for advanced AEM applications, particularly in water electrolysis..

A microphase-separated structure of polystyrene-b-polyisoprene-b-polystyrene triblock copolymers prepared via shear-press and injection molding methods during uniaxial deformation

The influence of the preparation method on the initial structure and deformation behavior of polystyrene (PS) - polyisoprene (PI) - PS (SIS) triblock copolymer elastomers was investigated using small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). Shear pressing (SP) and injection molding (IM) were used as the preparation methods. The samples exhibited a microphase-separated structure, in which the PS cylinders were packed in a hexagonal lattice for the entire sample. SP-SIS possessed a higher degree of microphase separation (DMPS) and an ordering of a microphase-separated structure (OMPSS), and lower degree of the PS cylinder orientation (DCO) than IM-SIS. Uniaxial tensile testing was performed along the parallel (//) and perpendicular (–|) directions to the PS cylinder orientation combining in situ SAXS/WAXD measurements. Young’s modulus and tensile strength of IM-SIS were lager and smaller than those of SP-SIS. A change in the PS cylinder orientation, which occurs for –| stretching, of IM-SIS occurred at larger strain than SP-SIS, indicating that the orientation of highly ordered PS cylinders are difficult to be changed due to their larger domains. It was found that the DCO relates to Young's modulus, yielding, and change in the PS cylinder orientation, while the OMPSS and DMPS relate to tensile strength.

Synthesis of poly(terphenyl-co-dibenzo-18-crown-6 methylimidazole) copolymers for high-performance high temperature polymer electrolyte membrane fuel cells

This study focuses on the development of high temperature polymer electrolyte membranes (HT-PEMs), which are essential components for HT-PEM fuel cells (HT-PEMFCs). While phosphoric acid (PA) doped polybenzimidazole (PBI) has been recognized as a successful HT-PEM, it faces several challenges, including the use of carcinogenic monomer, complex synthesis processes, and poor solubility in organic solvents. To produce more cost-effective, easily synthesized, and high-performance alternatives, this study utilizes a straightforward superacid-catalyzed Friedel-Crafts reaction to synthesize a series of poly(terphenyl-co-dibenzo-18-crown-6 methylimidazole) copolymers, referred to as Co-x%TP-y%CE-Im, using p-terphenyl, dibenzo-18-crown-6 and 1-methyl-1H-imidazole-2-formaldehyde as monomers. The copolymerized hydrophilic and bulky crown ether units introduce substantial free volume and multiple interaction sites with PA molecules, as indicated by theoretical calculations. Additionally, the formation of microphase separation structures, confirmed by atomic force microscope (AFM) and transmission electron microscope (TEM), contributes to the enhanced performance of these membranes. For instance, after immersion in 85 wt% and 75 wt% PA solutions, the Co-90%TP-10%CE membrane achieves PA doping contents of 200 % and 169 %, achieving high conductivities of 0.092 S cm−1 and 0.054 S cm−1 at 180 °C, while maintaining tensile strengths of 6.5 MPa and 7.5 MPa at room temperature. Without the need for humidification or backpressure, the peak power density of an H2-O2 cell equipped with Co-90%TP-10%CE/169%PA membrane with a thickness of 79 μm reaches an impressive 1018 mW cm−2 at 210 °C. These results demonstrate new materials and insights for the development of high-performance HT-PEMs.

Distinguish microphase-separated structures of diblock copolymers using local order parameters

The microphase-separated structures of block copolymers are inherently highly ordered local structures, commonly characterized by differences in domain width and curvature. By focusing on diblock copolymers, we propose local order parameters (LOPs) that accurately distinguish between adjacent microphase-separated structures on the phase diagram. We used the Molecular Assembly structure Learning package for Identifying Order parameters (MALIO) to evaluate the structure classification performance of 186 candidate LOPs. MALIO calculates the numerical values of all candidate LOPs for the input microphase-separated structures to create a dataset, and then performs supervised machine learning to select the best LOPs quickly and systematically. We evaluated the robustness of the selected LOPs in terms of classification accuracy against variations in miscibility and fraction of block. The minimum local area size required for LOPs to achieve their classification performances is closely related to the characteristic sizes of the microphase-separated structures. The proposed LOPs are potentially applicable over a large area on the phase diagram.

Triphenylamine branched poly(aryl piperidinium) anion exchange membrane for alkaline water electrolyzers

Coordinating the “trade-off” effect between ion conductivity and dimensional stability of anion exchange membranes (AEMs) is a key issue for the industrialization of AEM water electrolyzers (AEMWEs). To resolve this dilemma, a series of branched quaternized poly(p-terphenyl-triphenylamine-piperidinium)-x (QPTAP-x) AEMs are fabricated by inserting various molar percentage of triphenylamine into ether-free poly(p-terphenyl piperidinium). This branched polymer structure not only promotes the fabrication of the microphase separation structure, reducing ion transport resistance, but also contributes to the generation of the branched network structure, improving the dimensional stability and mechanical properties of the membrane. QPTAP-5.0%, a membrane with a triphenylamine content of 5.0%, exhibits the highest conductivity (174.63 mS cm−1 at 80 °C), low water swelling ratio (17.59% at 80 °C), and excellent mechanical properties (TS of 48.30 MPa and EB of 40.32%). Furthermore, it exhibits excellent alkaline stability and maintains 74.8% of conductivity after treated in 3 M KOH at 80 °C for 1440 h. The AEMWE based on QPTAP-5.0% achieves a current density of 1.6 A cm−2 at 2.2 V. The results suggest the significant potential of the triphenylamine-branched QPTAP-x for future AEMWE applications.

Robust branched Poly(p-terphenyl isatin) anion exchange membranes with enhanced microphase separation structure for fuel cells

Anion exchange membrane fuel cells (AEMFCs) are gradually becoming the focus of sustainable hydrogen energy research due to the advantages of clean by-products, faster oxidation-reduction dynamics and allowing cheap platinum-free base materials. As the key components of AEMFCs, anion exchange membranes (AEMs) are required to have high ionic conductivity and dimensional stability. This study focused on the design and preparation of branched AEMs for AEMFCs. The b-PTIN-x membranes were generated by incorporating 1,3,5-triphenylbenzene (TPB) units into rigid poly(p-terphenyl isatin) (PTI) polymer backbones. This innovative approach aimed to induce microphase separation structures by exploiting TPB with high FFV, as well as to enhance the tensile strength of AEMs with the help of branched structures. SAXS and AFM images revealed that the AEMs achieved enhanced microphase separation structures, resulting in the formation of ion transport channels with dimensions in the range of a few nanometers (3.36–3.70 nm). The branched b-PTIN-11 membranes displayed significant OH− conductivity (153.9 mS cm−1 at 80 °C) while having a low ion exchange capacity (IEC) (1.73 mmol g−1). The b-PTIN-11 membranes displayed improved tensile strength (56.69 MPa) and exceptional dimensional stability, with swelling ratio (SR) of 18.5 % at 80 °C. They also showed great chemical stability with 89.64 % conductivity remaining, lasting for more than 1200 h in 3 M NaOH solution at 80 °C. Ultimately, the b-PTIN-11 membrane underwent testing to evaluate its performance in a fuel cell using H2–O2. It demonstrated a peak power density (PPD) of 566 mW cm−2 when subjected to a current density of 1339 mA cm−2.

Amphiphilic colloidal particles/Ca2+ reinforced edible agar nanocomposite film by multiple cross-linking/microphase separation strategies

The agar (AG) film exhibited poor mechanical and water-resistant properties which limited its application for food packaging. The structural modification of AG nanocomposite film greatly impacts their macroscopic properties. In this paper, edible AG nanocomposite films were achieved by incorporating colloidal particles based on conjugates of whey protein isolate (WPI) and alginate oligosaccharides (AOS) as the nanofiller to obtain the micro-phase separation structure and the multiple cross-linking network with the synergistic interactions of the Ca2+ crosslinking. Firstly, WPI-AOS colloidal particles were synthesized through the Wet-heating Maillard reaction. Good compatibility between WPI-AOS colloidal particles and AG was exhibited, resulting in improved mechanical and water-resistant properties of AG composite films. Compared to pure AG film, the tensile strength (TS) of the agar composite film with 10% WPI-AOS colloidal particles increased significantly to 81.87 MPa from 24.02 MPa, and the elongation at break (EAB) also improved to 46.25% from 18.65%. The moisture content (MC), water solubility (WS), and water vapor permeability (WVP) of the AG composite film decreased by 33.1%, 18.0%, and 22.4% respectively. In addition, the multiple cross-linking network hindered the relative sliding between the AG molecular chain, which resulted in improved thermal stability of the composite film. Using soft colloidal particles as nanofillers to fabricate edible films for improving their properties is an effective and promising strategy.

Multiphase hydrogen bonding strategies room temperature self-healing, recyclable polyurethane elastomers for applications in flame retardant materials

Novel elastomers offer new opportunities to develop multifunctional materials in terms of combining mechanical strength, room-temperature self-healing properties and recyclability. However, self-healing polymers have high mechanical strength at high internal cross-linking density, but restrict the movement of molecular chain segments leading to reduced self-healing efficiency. The presence of microphase-separated structures makes the polymers poorly efficient for repair at room temperature. In this paper, a multiphase hydrogen bonding (H-bonding) strategy is used to introduce an aliphatic ring into the system to form a repeating unit with the hard segments, as well as a bis-benzene ring structure with a methylene linkage to disrupt the crystallization of the hard domains. Specifically, PUPI-M2I3 has a mechanical tensile strength of 17.93 MPa, an excellent tensile ratio of 1109.88 %, the sample can recover 95.93 % at room temperature after 24 h of fracture and stretching, with excellent room temperature self-healing performance and recyclability. Meanwhile, the self-healing flame-retardant material based on PUPI-M2I3 is developed by comprehensive consideration, which opens a new way for the research and development of flame-retardant materials.

Synthesis of base-acid pair based poly(isatin arylene) membranes for HT-PEMFC applications

Phosphoric acid (PA) doped polymer electrolyte membranes are promising high temperature proton exchange membranes (HT-PEMs) for fuel cells. While PA doped polybenzimidazole (PBI) has been considered as a successful HT-PEM, several issues remain, such as the use of carcinogenic monomer, poor solubility in organic solvents and easy PA loss. To develop more cost-effective, readily synthesized and high-performance HT-PEMs, this study focuses on synthesizing high-performance HT-PEMs based on poly(isatin arylene)s (i.e., PIT and PIB) containing a lactam structure and devoid of ether bonds. These polymers are synthesized from isatin and p-terphenyl (or biphenyl) under superacid catalysis. Subsequently, glycidyl trimethyl ammonium chloride (GTA) is employed as a grafting reagent for PIT and PIB. This ring-opening reaction is accomplished through an efficient and environmentally friendly procedure without any alkaline catalysts. The introduced GTA side chains with quaternary ammonium and hydroxyl groups not only produce microphase separation structures that facilitate proton conduction, but also reduce PA loss. Comparing with PIT-GTA with terphenyl units, the PIB-GTA membrane with short biphenyl units exhibits superior properties. For instance, the PIB-GTA/218.5%PA membrane achieves a high conductivity of 0.103 S cm−1 at 180 °C and a tensile strength of 6.6 MPa at room temperature. Without humidification and backpressure, the PIB-GTA/218.5%PA based H2–O2 single cell displays a peak power density of 632 mW cm−2 at 160 °C. This work presents a straightforward approach to synthesizing GTA grafted poly(isatin arylene) membranes for HT-PEM fuel cells.

A novel high-molecule inorganic composite material with excellent elasticity and toughness used in tunnel isolation – Material design and basic mechanical properties

Cross-sea engineering plays a crucial role in the advancement of human society. However, due to geological constraints, cross-sea tunnels, as the primary infrastructure of such projects, are prone to instability and compromised safety during severe seismic events. Existing tunnel isolation materials face challenges such as susceptibility to cracking and difficulty in withstanding cyclic loads. Therefore, the development of tunnel isolation materials with strong elasticity and toughness is of significant importance. This study addresses this need by developing a high-elasticity, super-tough polymer-inorganic composite tunnel isolation material. Drawing on the microphase separation structure of polyurethane elastomers and polymer-based composite material interfaces, the innovative material was synthesized and characterized. Uniaxial and cyclic loading tests were conducted to evaluate its mechanical behavior, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to examine filler-polyurethane matrix bonding, microstructural changes, and interface modifications. These analyses revealed the synergistic mechanisms of the composite components. Results demonstrated significant enhancements in compressive performance and unit volume energy consumption, with the elastic modulus controllable at approximately 10 MPa, and the strain recovery rate stabilizing at 82 %. Moreover, a mix design model was developed for predicting compressive strength, elastic modulus, tensile strength, and elongation at break concerning PVA fiber content.

Self-consistent field theory for loop-containing polymers: A general algorithm for path-determination

An algorithm was developed for self-consistent field theory (SCFT) simulations of loop-containing polymers (LCPs), where the total number of independent loops (fundamental cycles in the polymer structure) is characterized by the “cycle rank.” Although various multi-ring and cage-like polymers have been reported, there is no explicit SCFT scheme for LCPs with multiple loops. An LCP was cut to open its fundamental cycles to form a pseudo-tree-like polymer. Conventional SCFT calculations for pseudo-tree-like polymers require extra spatial constraints on the pseudo-free endpoints generated by opening the fundamental cycle, which increases the computational cost. A reduction in the computational cost was observed, and the algorithm was applied to microphase-separated structures of small LCPs.

Microphase Separation and Gelation through Polymerization-Induced Self-Assembly Using Star Polyethylene Glycols.

Polymerization-induced self-assembly (PISA) during the synthesis of diblock copolymers has garnered considerable interest; however, architectures beyond diblock copolymers have scarcely been explored. Here, we studied PISA using 4- and 8-arm star polyethylene glycol (PEG), as well as 2-arm (linear) PEG, wherein each terminus of PEG was functionalized with a chain-transfer agent, holding a constant molar mass for each arm. Styrene was polymerized from each PEG terminus through reversible addition-fragmentation chain-transfer (RAFT) polymerization in an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6]), with a total solute concentration of 40 wt %. While the styrene monomer is soluble in [BMIM][PF6], polystyrene is not; thus, self-assembly and cross-linking (gelation) occur. Structural analysis by small-angle X-ray scattering revealed that a relatively ordered microphase-separated structure for PISA was observed. Two-arm PEG-PS formed hexagonally packed cylinders, whereas 4- and 8-arm PEG-PS exhibited hexagonal close-packed spheres and disordered spheres. The dynamics, studied by oscillatory rheology, were also influenced by the number of arms; the 4-arm star block copolymers showed the highest plateau modulus. This study demonstrates that the topology is an important factor in controlling the microphase-separated structure and mechanical properties when preparing gels through PISA.

Tailoring physicochemical properties of quaternized polystyrene-ethylene/butylene-styrene membrane for enhanced pervaporation desalination

Pervaporation offers unique advantages for desalination of hypersaline water using highly hydrophilic and selective membrane. Positively charged membrane is superior in repelling cations and preventing scaling through electrostatic repulsion. This study investigates the quaternization and crosslinking of block copolymer styrene-ethylene-butylene-styrene (SEBS) membrane and explores the potential of quaternized membrane for pervaporation desalination. A one-step immersion process was proposed to easily adjust the physicochemical properties of membrane using trimethylamine (TMA) and N,N,N′,N′-tetramethyl-1,6-hexanediamine (TMHDA) for ammonium grafting and crosslinking. Compared to the quaternization with TMA or TMHDA alone, the combination of TMA and TMHDA produces a synergistic effect, improving crosslinking efficiency and facilitating the grafting reaction. This results in high ion exchange capacity (IEC) values and a transformation of microphase separation structure with more interconnected hydrophilic domains. An ultrahigh water permeability coefficient of 0.6 × 106–1.2 × 106 Barrer and highly intrinsic salt rejection were obtained in treating 3.5–20 wt% NaCl solution. The thin film composite QEBS/nylon membranes showed a superior water flux of 116.5 kg·m−2·h−1 and salt rejection of >99.99 % in desalinating 5 wt% NaCl solution at 85 °C. Additionally, the membrane exhibited excellent long-term performance stability and resistance to acid and alkali environment, showing great potential for desalination of hypersaline water.

Poly(p-terphenyl-piperidine-bromoacetophenone) anion exchange membranes with pendant N-spirocyclic cations: Cations synergistic build efficient ion transport networks

The establishment of well-developed ionic conduction channels and the preparation of excellent chemical stability are urgent needs for anion exchange membranes. In this study, we successfully prepared poly (p-terphenyl-piperidine-bromoacetophenone) polymers using superacid catalysis. Then a series of QPTPP-N-ASU-x AEMs were prepared by introducing N-spirocyclic side chain cations (N-ASU) with different grafting rates. The introduction of N-spirocyclic cations with better alkali resistance increases multiple OH− transport sites, contributes to the microphase separation structure, and is synergistic with piperidine cations to rapidly construct ion transport networks, giving the membranes good conductivity and alkali resistance stability. The AFM showed that QPTPP-N-ASU-5% AEM had a remarkable microstructure and formed large ionic domains, the conductivity of the membrane was 121.2 mS cm−1, corresponding to a peak power density of 477.25 mW cm−2. The conductivity residual of QPTPP-N-ASU-5% AEM was 94.15 % and 87.71 % after immersion in 2 M and 4 M NaOH at 80 °C for 1440 h. It shows that membrane has good potential for application.

Effect of carbon black on the liquidity and compression performance of Polyurethane-Based tunnel isolation materials

Cross-sea engineering plays a vital role in the development of human society. However, due to geological constraints, cross-sea tunnels, as the main form of cross-sea engineering structures, are susceptible to instability and safety risks under strong seismic forces. Therefore, the development of tunnel isolation materials with strong elasticity and toughness is of great significance. In this study, a polyurethane-based tunnel isolation material was developed, and its liquidity, compression performance, and microstructure were investigated. The results show that, due to the improvement of the polyurethane microphase separation structure by carbon black, the compression performance of the material can be effectively enhanced, with a compressive strength of up to 1.88 MPa. Additionally, the material’s liquidity meets construction requirements, and its elastic modulus is relatively low, around 15 MPa, which meets the requirements for isolation.

A soluble highly-sulfonated polybenzimidazole with high molecular weight as membrane for vanadium flow battery with enhanced performance and long-term stability

A series of novel sulfonated polybenzimidazole (SPBI) membranes containing flexible double ether segments, having high ion exchange capacity (IEC), good solubility as well as high molecular weight, are designed for vanadium flow batteries (VFBs). The bis-ether structure of self-synthesized sulfonic acid monomer, 4,4'-((2-sulfo-1,4-phenylene)bis(oxy))dibenzoic acid, improves the solubility of produced SPBI and the microphase separation structure of prepared membrane by disrupting the regularity of the backbone through a non-planar structure and attenuating the interchain stacking effect of the polymer backbone. Such a highly reactive bis-ether monomer also leads to high molecular weights (2.37−2.82 dL g−1). The copolymerization using another sulfonic acid monomer, Monosodium-5-Sulfoisophthalate monomer, leads to a high IEC of up to 2.08 mmol g−1. As a result, the SPBI membrane shows a low area resistance of 0.21 Ω cm2 and a low vanadium ion permeability of 3.36 × 10−9 cm2 s−1. The VFB cell employing SPBI membrane achieves a very high energy efficiency exceeding 82 % at 200 mA cm−2. In addition, an ultra-long lifetime of over 3400 cycles is accomplished.