Flexible Crosslinking Research Articles

Filaminopathy type C

Filamin is an actin-binding protein that, by forming flexible molecular cross-links, stabilizes the three-dimensional F-actin networks and gives them the mechanical properties of a gel. It is represented by three isoforms: filamine A (FLNA), filamin B (FLNB), and filamin C (FLNC), derived from 3 homologous genes. Laminopathies caused by mutations in the FLNA, FLNB, and FLNC genes represent an extensive allelic series of diseases. The review discusses in detail the genotype-phenotypic correlation of all types of phylaminopathies. The neuromuscular and cardiac clinic of C-type phylaminopathy is described in detail. Three variants of C phylaminopathy known at the moment are analyzed.

Design of Metal-Organic Framework Templated Materials Using High-Throughput Computational Screening.

The ability to crosslink Metal-Organic Frameworks (MOFs) has recently been discovered as a flexible approach towards synthesizing MOF-templated “ideal network polymers”. Crosslinking MOFs with rigid cross-linkers would allow the synthesis of crystalline Covalent-Organic Frameworks (COFs) of so far unprecedented flexibility in network topologies, far exceeding the conventional direct COF synthesis approach. However, to date only flexible cross-linkers were used in the MOF crosslinking approach, since a rigid cross-linker would require an ideal fit between the MOF structure and the cross-linker, which is experimentally extremely challenging, making in silico design mandatory. Here, we present an effective geometric method to find an ideal MOF cross-linker pair by employing a high-throughput screening approach. The algorithm considers distances, angles, and arbitrary rotations to optimally match the cross-linker inside the MOF structures. In a second, independent step, using Molecular Dynamics (MD) simulations we quantitatively confirmed all matches provided by the screening. Our approach thus provides a robust and powerful method to identify ideal MOF/Cross-linker combinations, which helped to identify several MOF-to-COF candidate structures by starting from suitable libraries. The algorithms presented here can be extended to other advanced network structures, such as mechanically interlocked materials or molecular weaving and knots.

Rigid crosslinkers towards constructing highly-efficient ion transport channels in anion exchange membranes

Synthetic anion exchange membranes (AEMs) usually suffer from low conductivity, bad alkaline stability and poor dimensional stability. Constructing efficient ion transport channels is considered to be one of the most effective ways for preparing the AEMs with the high conductivity and low swelling ratio. Herein we demonstrate a facile strategy to achieve this goal via using the rigid crosslinkers to expend the interchain spacing of polymer chains. Three crosslinkers are chose to modify poly (ether ketone) (PEK) AEMs. The AEMs with rigid crosslinkers have more efficient ion transport channels and thus show both higher water uptake and higher ionic conductivity, compared with the AEM with the flexible crosslinker. Especially, the hydroxide conductivity of the AEM increases from 63.2 to 110.3 mS cm−1 at 80 °C when the short flexible crosslinker is replaced by the long rigid crosslinker. Meanwhile, the swelling ratios (SR) are less than 25%. The rigid crosslinkers should be beneficial to construct efficient ion channel and overcome the trade-off relation between the ionic conductivity and dimensional stability of the synthetic AEMs.

Static and dynamic comfort properties of polyurethane foams including a flexible amine crosslinker

Flexible polyurethane (PU) foams are widely used in various automobile products for seat cushioning, sound absorbing, and heat insulating purposes. The PU foams were fabricated by applying hydroxyl and amine types of crosslinking agents in order to examine the static and dynamic comfort properties. The bis(hexamethylene)triamine (BHMTA) crosslinker produced the largest cell and pore sizes due to the highest drainage flow rate, but the diethylenetriamine (DETA) crosslinker led to the smallest sizes due to the increased reactivity and hydrogen bonding. The cell wall area ratio resulted in the highest with the DETA and the lowest with the BHMTA, and this cell wall area has a strong relation with the hysteresis loss (low with BHMTA vs. high with DETA). The sag factor was the highest with the BHMTA due to the lowest stress value at 25% strain. The vibration transmissibility was the lowest with the BHMTA crosslinker due to the lowest cell wall area ratio. Therefore, it is critical to choose a proper crosslinking agent in fabrications of the flexible PU foams for superior static and dynamic comfort properties.

Cyclodextrin modified, multication cross-linked high performance anion exchange membranes for fuel cell application

The anion exchange membranes (AEMs) with high hydroxide ion conductivity and stability are in an urgent need for alkaline membrane fuel cell applications. High ionic exchange capacity (IEC) is necessary to improve conductivity but detrimental to stability. In this work, a series of novel AEMs modified with bulky rigid β-cyclodextrin (CD) and long flexible multiple quaternary ammonium (MQ) are designed and prepared. The resulting AEM with a relatively low IEC of 1.50 mmol g-1 shows a good hydroxide ion conductivity of 112.4 mS cm-1 at 80 oC, whereas its counterpart without CD modification exhibits 83.0 mS cm-1 despite a similar IEC (1.60 mmol g-1); this is because the large CD units can impart high free volume to the membrane, reducing the ion transport resistance, and meanwhile, the hydrophilicity of CD’s external surface may promote formation of ion transport channels across the long flexible MQ cross-links. The CD modified AEM also imparts the membrane a better alkali- and swelling resistance as well as a higher tensile strength, without sacrificing its hydroxide ion conduction properties, than the un-modified membrane. The H2–O2 fuel cell yields a high peak power density of 288 mW cm-2 at 60 oC. Our work implies that the CD enabled free volume strategy is effective to balance conductivity and stability, which may pave the way to fabrication of AEMs with further improved performance.

Simultaneously achieving high strength, thermal resistance and high self‐healing efficiency for polyacrylate coating by constructing a Diels–Alder reversible covalent structure with multi‐maleimide terminated hyperbranched polysiloxane

AbstractIt is difficult for the self‐healing polyacrylate coatings reported so far to simultaneously achieve high mechanical strength and high self‐healing efficiency within a short healing time. Herein, derived from multi‐maleimide terminated hyperbranched polysiloxane, linear polyacrylate with furan‐containing side chain and polydopamine particles (photothermal conversion agent), a new kind of polyacrylate coating (HPA) with a strong and flexible crosslinking network was developed, which simultaneously shows high mechanical strength and high self‐healing efficiency within a short time. With 0.3 wt% polydopamine particles in HPA, the resulting coating (HPA3) has the highest toughness (2.63 ± 0.10 MPa) with 12.9 ± 0.7 MPa tensile strength and 23.9% ± 1.6% elongation at break; in addition, the self‐healing efficiency of HPA3 is over 87.6% after only 2.5 min of near‐infrared laser irradiation, overcoming intractable problems in developing self‐healing polyacrylate coatings. A study of the mechanism behind these outstanding performances of the HPA system reveals that the reversible covalent crosslinking formed by multi‐maleimide terminated hyperbranched polysiloxane is the necessary and crucial factor for simultaneously achieving high mechanical strength and high self‐healing efficiency in a short time. © 2019 Society of Chemical Industry

Phase change material with flexible crosslinking for thermal energy storage

ABSTRACTThe utilization of renewable energy through phase change materials (PCMs) is particularly attractive for the realization of sustainable society. Herein, a flexible but reliable solid–solid PCM was successfully synthesized by the integration of quadruple H‐bonding crosslinks with polyethylene glycol (PEG)‐based polyurethanes. The strong quadruple H‐bonding from the dimerization of 2‐ureido‐4 [1H]‐pyrimidinone (UPy) units could act as dynamic cross‐links to maintain shape stability. PEG chains in flexible polymer network serve as phase change ingredients, affording thermal energy storage capacity. The physical crosslink density and phase change enthalpy can be adjusted. In contrast to chemical crosslinks, the physical crosslinks of UPy provide reprocessability of the prepared PCMs and show little hindrance on the crystallization of PEG chains. The chemical structure, phase transformation, crystallization, and thermal properties of prepared PCMs were characterized by fourier transform infrared spectroscopy, differential scanning calorimetry (DSC), X‐ray diffraction, polarizing microscope, and thermogravimetric analysis. DSC analysis shows that the prepared PCM can store 101.9 J g−1 when PCMs undergo phase change process. Moreover, the accelerated thermal cycling test and leakage test are also conducted to illustrate the thermal reliability and shape‐stable properties. These PCMs that possess high phase change enthalpy and outstanding reprocessability are alternative for solar energy collection and waste heat recovery. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48497.

Tunable multi-cations-crosslinked poly(arylene piperidinium)-based alkaline membranes with high ion conductivity and durability

A practical polyelectrolyte system to improve the ion conductivity and lifetime of anion exchange membranes (AEMs) is a critical requirement for alkaline membrane fuel cells (AMFCs). Crosslinking is an effective approach to optimize the performance of AEMs. However, ordinary crosslinkers with a hydrophobic structure always make AEMs mechanically brittle. Herein, in response to the requirement of high-performance AEMs, a series of tunable multi-cation-crosslinked poly(biphenyl piperidinium) (PBP-xQ4) membranes were designed and prepared by embedding flexible cationic crosslinkers. The number of alkyl spacers between the cationic groups in the flexible crosslinkers were optimized to 5 and 6 to achieve optimum performance. These PBP-xQ4 membranes simultaneously have high ion conductivity (155 mS/cm at 80 °C) and good dimensional stability, and these membranes can be folded into many shapes. Besides, the crosslinking also promotes the alkaline stability of these membranes in 2 M NaOH at 80 °C: only a slight degradation is detected by 1HNMR after alkaline treatment for1800 h. All these impressive results in ion conductivity and durability are attributed to clear nanophase separation in PBP-xQ4 membranes. Moreover, the PBP-xQ4 membrane realizes a maximum power density of 234 mW/cm2 at 80 °C.

Amino acid salt-driven planar hybrid perovskite solar cells with enhanced humidity stability

While hybrid perovskites have great potential as light-absorbing materials, they suffer from moisture-induced instability. Herein, we added the amino acid iodide salt-based molecular crosslinker p-aminobenzoic acid (PABA∙HI) to a perovskite precursor solution to enhance the humidity stability. The rigid molecular structure of PABA∙HI played an important role in determining the crystal orientation, trap density, and photovoltaic performance of the perovskite solar cells (PVSCs). PABA∙HI can effectively interact with the Pb-I framework via hydrogen bonds, enhancing the crosslinking efficiency compared with freely rotating flexible molecular crosslinkers. Kelvin probe force microscopy in conjunction with Raman analysis confirmed the presence of PABA∙HI at the grain boundaries; thus, stable quasi-two-dimensional perovskite existed along the grain boundaries, passivating the grain boundaries and improving the moisture stability. The PABA∙HI-added PVSCs having a power-conversion efficiency (PCE) of 17.4% retained 91% of their initial PCE when stored for 312 h at a relative humidity of 75% at 25 °C, whereas a pristine cell with a PCE of 16.4% only retained 37% of its initial value. Our findings clearly indicate that the amino acid salt as a rigid molecular crosslinker improved not only the photovoltaic performance but also the stability against moisture.

Unraveling bio-inspired pre-swollen effects of tetra-polyethylene glycol double network hydrogels with ultra-stretchable yielding strain

Incorporating flexible cross-links into a brittle network for hydrogel not only significantly improves its toughness, but also effectively provides opportunities to design novel double network (DN) hydrogels with targeted properties and multi-functionalities. However, the principles and toughening mechanisms behind many of experimental studies have not been investigated. In this paper we proposed, for the first time, a phenomenological model for the DN hydrogels, which were derived from tetra-polyethylene glycol (tetra-PEG) first network, molecular stent and polyacrylamide (PAAm) second network, and theoretically and experimentally studied the pre-swollen effects on their ultra-stretchable yielding strains. Based on the Flory–Huggins solution theory, the pre-swollen effect of polar molecular stents on the mechanical properties of tetra-PEG/PAAm DN hydrogels was investigated. Finally, the constitutive stress–strain relationships of two-stage loading process were established for the overall response of mechanical behavior, and a good agreement between the numerically simulated results with the experimental ones has been achieved. This study provides a fundamental understanding of the working mechanism of pre-swollen effects and the design guidance for the ultra-stretchable and toughened DN hydrogels.

Development and Characterization on sound acoustic at photo-induced polymer foam composited at prolonged ultra-violet exposure

In this paper, polymer foam composites (FC) have been developed based on polyol mixed flexible crosslinker and fibre filler of Meranti Merah. 10 mm, 20 mm and 30 mm thickness of foam polymer and its composites have been use in this study. The percentage loading of wood fibre of 5%, 10%, 15% and 20% added with polymer foam is namely as polymer foam (PP) and its composites of PP5, PP10, PP15 and PP20. The sound absorption coefficient (α) and pore structure of the foam samples have been measure by using Impedance Tube test and Scanning Electron Microscopy (SEM). UV Weatherometer is used to examine the durability and weatherproof of its composite. The results show that the highest thickness of the highest percentage fiber filler (Pp2030) gives higher sound absorption coefficient (α). 0.9922 and 0.99889 which contributed from low and high frequency absorption level respectively. The smallest pores size structure was observed with highest filler loading of PP20. The higher the thickness and the higher the percentage loading of wood filler gives smaller pore structure, consequently, increased the sound absorption coefficient level. Meanwhile, the stability of polymer foam composites is high due to unchanged pore structures morphology with prolonged ultra violet exposure.

Lightweight and flexible electrospun polymer nanofiber/metal nanoparticle hybrid membrane for high-performance electromagnetic interference shielding

To resist the increasingly serious radiation pollution, there is a great need for the fabrication of high-performance electromagnetic interference (EMI) shielding materials. However, it is a great challenge to prepare EMI shielding materials with high efficiency, lightweight, and flexibility for practical applications. Here, we demonstrate an efficient and facile approach to prepare freestanding, lightweight, and flexible crosslinking polyacrylonitrile (CPAN) nanofiber (NF)/metal nanoparticle (MNP) hybrid membranes with a high efficiency and reasonable strength via electrospinning followed by an electroless deposition process. In contrast to a Cu- and Ni-decorated CPAN NF membrane, the resultant CPAN NF/Ag nanoparticle (NP) hybrid membrane exhibited much better electrical conductivity. Furthermore, a superior EMI shielding effectiveness of ≈90 dB is achieved for the lightweight CPAN NF/Ag NP hybrid membrane (53 µm), which is superior to pure metal and most of the synthesized EMI shielding materials. The excellent EMI shielding efficiency is attributed to the high conductivity of MNPs and favorable porous structure in the hybrid NF membrane. In addition, the resultant CPAN NF/MNP hybrid membrane shows a reasonable mechanical strength and excellent flexibility. The prepared polymer NF/MNP hybrid membrane shows promising applications in smart portable and wearable electronics.

Formation of Tough and Deformable Films through Evaporating Dispersions of Elastomer Microspheres By Crosslinked with Rotaxane

Downsizing polymer materials (<~10 micrometers) to the colloidal scale can be dispersed in the solvent and showed distinctly different behavior from the corresponding bulk materials. One of the most useful application of colloidal dispersions is that they are injectable, which significantly simplifies method of bulk materials. Compared to rigid microspheres based on polystyrene or silica, soft and deformable elastomer microspheres have been used to create colorless transparent films through solvent evaporation. In general, to obtain tough microsphere films, many additives are required, and/or post-polymerization modification is necessary. In this study, we synthesized elastomer microspheres cross-linked with rotaxane, and succeeded in getting tough films by simply evaporating water [1]. To obtain colloidal microspheres with flexible crosslinkers, a rotaxane crosslinker (RC), consisting of a crown ether wheel and an axle with one vinyl group per component. We selected mini-emulsion polymerization, in which an oil monomer droplet is polymerized to become a polymer microsphere, to sufficiently trap the RC within the microspheres because the RC hardly dissolves in water but can be dissolved in organic solvents or oil-monomers. Films were generated by depositing an elastomer microsphere dispersion on a silicon rubber sheet, followed by drying at room temperature and annealing effect. Tensile tests were performed at 25 °C at an elongation rate of 10 mm/min. The BM and BM-D0.05 films, in which the microspheres were crosslinked only physically and by conventional crosslinkers, were brittle because the chain entanglement between the microspheres was able to slip easily upon elongation, and the fracture energies (En ) of these films were <10 MJm-3. In contrast, BM-R0.05 film, where the microspheres were crosslinked by RC, reveal increased fracture stress and fracture strain (Figure 1). It suggested that the stress relaxation in each elastomer microsphere, originating from the flexibility of the crosslinking points, affected on the mechanical properties of the BM-R0.05 film, even though the post crosslinking reaction between the microspheres was not performed. The result of this study should find the advanced applications for such as in the areas of medicine and cosmetics, in which the minimization of impurities is desirable. Furthermore, the effect of film preparation condition will be discussed. Partially reproduced with permission from [1] Copyright (2018) John Wiley and Sons. Reference [1] S. Hiroshige, T. Kureha, D. Aoki, J. Sawada, D. Aoki, T. Takata, D. Suzuki, Chemistry - A European Journal, 2017, 23, 8405 – 8408. Figure 1

Ultrahigh oxygen permeability of chemically-modified membranes of novel (co)polyacetylenes having a photodegradative backbone and crosslinkable side chains

Four new partly modified membranes of novel (co)polyacetylenes having a photodegradative backbone and crosslinkable side chains showed excellent performances as oxygen permselective membranes, that is, ultrahigh oxygen permeability (PO2) with relatively high oxygen permselectivity (α = PO2/PN2). In α vs. PO2 plots, two of them showed a performance close to Robeson's upper bound 2008 and the other two exceeded Robeson's upper bound 1991. The combination of the rigid main chain of the (co)polymers, the regular structure of the supramolecular polymer, and the flexible crosslinking structure may have produced these excellent performances.

Cross-Linked Poly(vinylbenzyl chloride) Anion Exchange Membranes with Long Flexible Multihead for Fuel Cells

To enhance the ionic conductivity and mechanical property of the chemically stable aliphatic anion exchange membranes (AEMs), cross-linked poly(vinylbenzyl chloride) AEMs (PVBC-xQ4) bearing long flexible cross-linker chains with multiple quaternary ammonium (QA) head were prepared via a facile one-step process. The AEMs exhibit high conductivity and excellent mechanical property. The cross-linked AEMs excluding any other heteroatomic bond especially the sulfone linkage or ether bond in the backbone have robust alkaline stability, low water uptake, and good dimensional stability. A well-developed hydrophilic/hydrophobic phase separated morphology was observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The PVBC-50Q4 membrane with ionic exchange capacity (IEC) of 1.87 mequiv g–1 displays a highest ionic conductivity of 74.3 mS cm–1 at 80 °C. After tested in a 2 M aqueous KOH solution at 80 °C for 1300 h, 88% of the conductivity and 89% of the IEC were remained. Furthermore, ...

Cross-Linked Sulfonated Poly(arylene ether sulfone) Containing a Flexible and Hydrophobic Bishydroxy Perfluoropolyether Cross-Linker for High-Performance Proton Exchange Membrane

Here we show a simple and effective cross-linking method to prepare a high performance cross-linked sulfonated poly(arylene ether sulfone) (C-SPAES) membrane using bishydroxy perfluoropolyether (PFPE) as a cross-linker for fuel cell applications. The C-SPAES membrane shows much improved physicochemical stability due to the cross-linked structure and reasonably high proton conductivity compared to the non-cross-linked SPAES membrane due to the incorporation of flexible PFPE and the effective phase-separated morphology between the hydrocarbon and perfluorinated moieties forming well-connected networks. Under intermediate-temperature and low humidity conditions (90 °C, 50% RH, and 150 kPa), the membrane electrode assembly employing the C-SPAES membrane reveals an outstanding cell performance (1.17 W cm-2 at 0.65 V) ascribed to its reasonably high proton conductivity and enhanced interfacial compatibility between the perfluorinated moieties in the electrode and C-SPAES membrane. Furthermore, a hydration-dehydration cycling test result at 90 °C reveals that the C-SPAES membrane has notable durability against rigorous operating conditions.

Effects of Regular Networks Composed of Rigid and Flexible Segments on the Shape Memory Performance of Epoxies

A series of regular rigid–flexible cross-linking epoxy networks were prepared from dithiol allyl glycidyl ethers (DTAGEs) and 4,4′-diaminodiphenylmethane (DDM). In these networks, the chemical structure of DTAGEs was tidily flexible and that of DDM was simply rigid, which ensured the flexible segments were more distinguishable from the rigid units. The effects of regularity and rigid–flexible character of the networks on shape memory properties, especially shape recovery speed, were investigated in detail. It was found that the shape recovery speed was reversely proportional to the flexibility of the regular cross-linking networks. Compared with flexibility, regularity had a greater impact on the recovery speed. In addition, regularity had a significant influence on the recovery speed of the rigid units while it had little influence on that of the flexible segments. The well-designed regular rigid–flexible cross-linking networks exhibited excellent shape memory performance with high shape memory fixity (≥...

Happy Times for the Macromolecular Journals

Let's start the new year with some good news that we know a lot of you have been waiting for: from January 2018, there will no longer be color charges for any of the Macro­molecular Journals. We are looking forward to your colorful submissions! Speaking of submissions, we have seen a strong overall growth of 20% across all Macro­molecular journals over the last two years. This trend supports our moves to put more man-power into the Macromolecular titles and so, to further strengthen our poly­mer program, David Huesmann and Anne Pfisterer have been promoted to deputy editors for the whole Macromolecular family. You already know Anne as the editor responsible for Macromolecular Bioscience, and David from his work on Macromolecular Materials and Engineering. They will now play a bigger role in the whole Macromolecular family, supporting Mara Staffilani with Macromolecular Chemistry and Physics and further developing the family flagship Macromolecular Rapid Communications. In addition, we can count on the help of Bo Weng from our Beijing office and Christine Mayer with her expertise in bio-related topics and, of course, Stefan Spiegel remains in charge of our specialized titles Macromolecular Reaction Engineering and Macromolecular Theory and Simulations. Unfortunately, Szymon Wiktorowicz' responsibilities have shifted with the success of his other projects, resulting in his move away from peer-review to take a lead role in Advanced Science News and the development of video content. Although he will be missed a lot, we are sure he will continue to support the team wherever possible in his new role. For Macromolecular Materials and Engineering specifically, 2017 has been another successful year. We were able to again increase our impact factor to 2.86, the highest value in the history of the journal. Table 1 features our Top 5 downloaded papers in 2017, including a communication by Christoph Weder from our first issue of 2017, which has already been cited 11 times. We also published a special issue with Luana Persano, Andrea Camposeo, and Dario Pisignano on Electrospinning and Functional Nanofibers. The issue was highly praised for its great content as well as its beautiful cover by I.-D. Kim and D. Pisignano, which you can see in the middle of Figure 1 (mame.201600569). Our other two favorite covers represent the articles Mechanically Robust, Tough, and Self-Recoverable Hydrogels with Molecularly Engineered Fully Flexible Crosslinking Structure by H. Zhuo and W. Chen (Figure 1, left) mame.201700085 and Design and Fabrication of Fibrous Nanomaterials Using Pull Spinning by K. K. Parker, (Figure 1, right), mame.201600404. We would like to thank our readers, authors, reviewers, and board members for their continued support, and we are looking forward to a colorful 2018.

Post-Crosslinked Polyurethanes with Excellent Shape Memory Property.

Shape-memory polymers are highly desirable in implant biomaterials for minimally invasive surgical procedures. However, most of them lack suitable transition temperature, mechanical properties, and biodegradability. Here, a series of shape-memory polyurethanes are synthesized by postcrosslinking in hard-segment domains using a flexible crosslinker. The materials used are all nontoxic and biodegradable. Through postcrosslinking of unsaturated linear polyurethanes with flexible and biodegradable crosslinker, the crosslinked polyurethanes (CPUs) show good mechanical properties, excellent shape-memory property, and repeatability. The post-crosslinking structure and shape-memory mechanism of CPUs are investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, and dynamic mechanical analysis tests. The crosslinker endows the fixed phase enough crosslinking and inserts in the hard segments to give the fixed phase certain elasticity. The elastic hard segments make them form more hydrogen bonds with soft segments during shape deformation. The low-molecular-weight poly (ε-caprolactone) offers the samples a shape-memory transition temperature at around 37 °C, which is suitable for implant devices in vivo. This work expands CPUs with an elastic crosslinking structure as potential candidates for implant biomaterials. Since the post-crosslinking polymerization is facile, it can be convenient for industrial production.

Non-Perflourinated Ion Conducting Membranes with Internal Crosslinking Network for Vanadium Flow Batteries (VFBs)

Vanadium flow batteries (VFBs) have become one of the most promising technologies for large-scale energy storage due to its nature of high safety, long cycle-life and environment-friendly. As one of the key parts, a membrane mainly plays a role in separating positive electrolyte and negative electrolyte and transferring protons to complete current circuit. Currently, the common used membranes for VFBs are perflourinated ion exchange membrane (such as Nafion 115). However, the Nafion 115 could not meet VFBs large-scale application due to its high cost and low ion selectivity. Therefore, the non-perflourinated ion exchange membranes are used as a separator because of its high ion conductivity and high selectivity as well as low cost. However, the chemical stability of the non-perflourinated ion exchange membranes cannot satisfy long-time cycling in VFBs due to the introduction of ion exchange groups. To further improve the chemical stability of non-perflourinated ion exchange membranes, the anion exchange membrane with internal crosslinking structure is designed and fabricated (Figure 1-a). The internal crosslinking structure ensures high stability of a membrane due to decreasing membrane swelling. The energy efficiency (EE) of a single cell with the optimized membrane maintained around 80% and cycled more than 1500 charge-discharge process at the current density of 140 mA/cm2, which exhibited the longest cycling life under VFBs operating conditions among the reported non-perflourinated ion exchange membrane, as shown in Figure 1-a’. Even though the ion exchange membranes with internal crosslinking structure possess long cycle life in VFB, the chemical stability of the fabricated anion ion exchange membranes still cannot meet VFB practical application. To address this problem, the advanced charged sponge-like porous membranes with crosslinking structure are designed and fabricated via combining crosslinking structure with porous ion conducting membrane, showing in Figure 1-b. The sponge-like porous structure could inhibit vanadium ions transferring though membrane via the multi-layered barriers, thus improve membrane selectivity. The internal crosslinking structure will ensure excellently chemical stability under strong acid and oxidized environment as well. In Figure 1-b’, the single cell assembled with the optimized porous membrane exhibits a CE of more than 99% and an EE of over 80% at the current density of 120 mA/cm2 and cycles more than 6000 charge-discharge process, which exhibits a promising prospect in large-scale VFB application. In addition, the performance of fabricated porous membranes could be tuned via designing internal crosslinking structure (Figure 1 c and d), like constructing flexible crosslinking structure or decorating internal crosslinking structure with hydrophilic groups within membrane, which shows higher ion conductivity than initial membrane. Figure 1 non-perflourinated ion conducting membranes with internal crosslinking network Figure 1