Cationic Ammonium Groups Research Articles

Henkel‐like Decarboxylation Produces Mononuclear Arylalkalis, [4‐(CH3)3N(C6H4)M]+ which Hydrolyse and Undergo Surprising SN2 Reactions Between Alkali Hydroxides and (CH3)3NC6H5+

AbstractBenzoate substituted with a cationic quaternary ammonium group at the para‐position, [4‐(CH3)3N(C6H4)CO2], forms mononuclear alkali metal ion complexes, [4‐(CH3)3N(C6H4)CO2M]+ (M=Li, Na, K, Rb and Cs), which are observed by electrospray‐ionisation mass spectrometry. When mass selected and subjected to collision‐induced dissociation each of these complexes undergoes decarboxylation to produce the mononuclear arylalkali complex cations, [4‐(CH3)3N(C6H4)M]+, which subsequently react with water via hydrolysis to yield the quaternary ammonium cation, (CH3)3NC6H5+. The unexpected product ions, [M((CH3)2NC6H5)]+, [M(CH3OH)]+, and M+, which are associated with the hydrolysis pathway, suggest an unusual reaction occurring within the exit channel ion‐molecule complex, [(CH3)3NC6H5+MOH]+. DFT calculations were used to examine the: decarboxylation reaction of [4‐(CH3)3N(C6H4)CO2M]+, which readily proceeds via a four‐centred transition state; the hydrolysis and SN2 reactions accounting for formation of products in the exit channel, which are connected via a roaming mechanism in which the metal hydroxide moiety migrates from the para‐hydrogen of (CH3)3NC6H5+ to one of the methyl groups.

The robustness waterproof ionogel based on the phase separation to form soft hard heterostructures and the interaction of cation-π realizes underwater adhesion and sensing

Flexible ionic conductors hold significant promise for advancing the field of soft ion electronics in the future. However, the creation of flexible conductors that possess mechanical robustness, underwater adhesion and underwater motion monitoring remains a challenge. Drawing inspiration from the multiphase hetero structure found in biological connective tissues, such as high modulus fibers and low modulus water-rich matrices, this article proposes a one-pot polymerization in-situ design strategy to create a hydrophobic ionogel with a hetero structure of soft and hard domains. The mechanical robustness, elasticity, and toughness of the ionogel are achieved through a synergistic combination of a strong skeleton in the hard domain and an elastic matrix in the soft domain. Additionally,hydrophobic aromatic rings and quaternary ammonium cation simulated cation-π interactions in mussel foot silk protein. Upon contact with water, the hydrophobic clusters quickly aggregate, facilitating the expulsion of interfacial water and exposing salicylic acid groups and quaternary ammonium cationic groups, leading to outstanding underwater adhesion between the ionogel and various substrates. The resulting hydrophobic ionogel can be utilized in underwater wearable electronic devices for monitoring human movement and physiological information, underwater repair monitoring, and intelligent soft robotics, demonstrating its vast potential in the field of underwater sensors.

Immobilization of tetrabromidozincate(Ⅱ) anions on ion exchange resin for efficiently catalytic conversion of CO2 to cyclic carbonates

Integrating reactive Lewis acid sites and nucleophilic anions into porous materials is a promising approach to develop efficient heterogeneous catalysts for the cycloaddition of CO2 to epoxides (CCE) into cyclic carbonates. In this work, ZnBr42− coordination anions consisting of Zn2+ ions as Lewis acid sites and Br− ions as nucleophiles were immobilized on the poly (styrene–divinylbenzene) anion-exchange resin D201 containing quaternary ammonium cationic groups through a simple ion-exchange method. The obtained catalyst, named ZnBr4-D201, was characterized by X-ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM) and thermo-gravimetry (TG). Under the condition of solvent and co-catalyst free, ZnBr4-D201 exhibited efficient catalytic activity for CCE reaction. Take the cycloaddition of CO2 to 1,2-epoxybutane (BO) as an example, ZnBr4-D201 gave a BO conversion rate of 97 % and a selectivity of 98 % for cyclic carbonate with a high TOF value at 1 MPa CO2 and 80 °C for 6 h, which is superior to most of heterogeneous catalysts ever reported. Furthermore, ZnBr4-D201 showed good recoverability, and the yield of cyclic carbonate was still up to 82 %. The excellent catalytic performance and convenient preparation process make ZnBr4-D201 have great potential for CCE reaction in practical production.

Physical, antibacterial, blood coagulation, and healing promotion evaluations of chitosan derivative-based composite films

Chitosan is a potentially suitable material for wound dressing, but is undesirably water-insoluble. Although chitosan can be modified to produce water-soluble derivatives, the best chitosan derivative for wound dressings remains unclear. The present study introduced three water-soluble chitosan derivatives, namely, carboxymethyl chitosan, quaternized chitosan (QCS), and carboxymethyl quaternized chitosan, and explored the physical properties, biochemical properties, and wound care effectiveness of films of these derivatives. The QCS-based film exhibited higher absorption ability, mechanical properties, water-vapor permeability, electroconductivity, and antioxidant capacity than the other films. Most importantly, the cationic quaternary ammonium groups facilitated the antibacterial activity (>95 %) and blood coagulant capacity of the QCS-based film. As this film also promoted wound healing, it presented as an ideal candidate for wound dressings.

Preparation and antibacterial ability of photodynamic antibacterial nanoparticles with ammonium cationic groups

With the increasing infection of drug-resistant bacteria, it has become a great challenge for researchers to find new approaches to eradicate drug-resistant bacteria and their biofilms. Photodynamic antimicrobial chemotherapy (PACT) is an indispensable part of the new anti-bacterial strategy because of its unique anti-bacterial mechanism, which can effectively inactivate drug-resistant bacteria without inducing further drug resistance. In this work, nanoparticles with N-isopropylacrylamide and methacryloxyethyltrimethyl ammonium chloride as monomers, and loaded with a fluorescent conjugated polymer were successfully prepared by microemulsion polymerization. The average particle size ranged from 100 to 200 nm. The nanoparticles could disperse in water steadily according to their zeta potential analysis. The nanoparticles generated singlet oxygen upon exposing to light with wavelength of 500–700 nm. Their PACT efficiency was investigated against Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus respectively. The results indicated that the antibacterial ability of nanparticles were excellent as the concentration was more than 0.01 mg/mL and the illumination time was 30 min. When the mass concentration of the nanoparticles was equal to or more than 0.05 mg/mL, the antibacterial mechanism was dominated by cation action, and when the concentration was equal or lower than 0.01 mg/mL, the antibacterial ability of the nanoparticles was improved effectively by photodynamic action. The antibacterial rate of the nanoparticle solutions against the bacteria in the biofilm was quantitatively studied, and it was proved that the nanoparticles eliminated bacteria in the biofilm effectively with a nanoparticle concentration of 0.2 mg/mL or more. The results indicated that the nanoparticles could effectively penetrate the biofilm to kill bacteria inside the biofilm by light illumination.

Synthesis, characterization and performance of quaternized cellulose based flocculant derived from office paper waste for dye removal

Abstract The quaternized cellulose derivatives (QCs) were synthesized by reacting extracted cellulose from office paper waste with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) in an aqueous solution of sodium hydroxide (NaOH) – urea. The characterization results by using Fourier-Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the office paper waste properties changed after chemical treatment and the extract product was confirmed cellulose. In addition, the FT-IR and SEM results confirmed the successful introduction of cationic quaternary ammonium groups into the main chain of cellulose. Meanwhile, the XRD results revealed that the crystalline structure was destroyed during etherification reaction. By using synthetic Congo red dye, the flocculation performance of the QCs was evaluated via standard jar test method at different QC dosages, initial Congo red dye concentration and pH values. It was found that the QC10 exhibited a more effective flocculation capability as compared to other synthesized QCs for over a wide pH value. The QC10 performed the best at pH 7, 100 mg/L of Congo red dye concentration and 50 mg/L of QC dosage, with percentage removal of 89.09 %. These findings demonstrated the potential application of QC in dye removal.

Ionic Strength-Dependent Structure of Complex Coacervate Core Micelles.

Salt concentration-dependent structure of complex coacervate core micelles (C3Ms), formed by polyether-based block copolyelectrolytes containing cationic ammonium (A) or anionic sulfonate (S) groups in aqueous media, is investigated by light scattering and small-angle X-ray/neutron scattering (SAX/NS). As the salt concentration increases, both a core radius (Rcore) and an aggregation number (Nagg) significantly decrease, but a corona thickness (Lcorona) is nearly unchanged. Larger salt concentrations can lower the interfacial tension between the coacervate cores and aqueous media, resulting in an increased interfacial area per chain and a more relaxed conformation of the core blocks. Based on the structure characterization, the scaling relationship between structure parameters (i.e., Rcore, Nagg, and Lcorona) and salt concentration is obtained and compared to the theoretical description estimated by the free energy balance between the entropic penalty of core stretching and the interfacial energy. We propose that the free energy contribution of the core block stretching is not negligible in C3Ms because of the highly swollen cores caused by water.

Cycloaliphatic Quaternary Ammonium Functionalized Poly(oxindole biphenyl) Based Anion-Exchange Membranes for Water Electrolysis: Stability and Performance.

Mechanically robust anion-exchange membranes (AEMs) with high conductivity and long-term alkali resistance are needed for water electrolysis application. In this work, aryl-ether free polyaromatics containing isatin moieties were prepared via super acid-catalyzed copolymerization, followed by functionalization with alkaline stable cyclic quaternary ammonium (QA) cationic groups, to afford high performance AEMs for application in water electrolysis. The incorporation of side functional cationic groups (pyrrolidinium and piperidinium) onto a polymer backbone via a flexible alkyl spacer aimed at conductivity and alkaline stability improvement. The effect of cation structure on the properties of prepared AEMs was thoroughly studied. Pyrrolidinium- and piperidinium-based AEMs showed similar electrolyte uptakes and no obvious phase separation, as revealed by SAXS and further supported by AFM and TEM data. In addition, these AEMs displayed high conductivity values (81. 5 and 120 mS cm-1 for pyrrolidinium- and piperidinium-based AEM, respectively, at 80 °C) and excellent alkaline stability after 1 month aging in 2M KOH at 80 °C. Especially, a pyrrolidinium-based AEM membrane preserved 87% of its initial conductivity value, while at the same time retaining its flexibility and mechanical robustness after storage in alkaline media (2M KOH) for 1 month at 80 °C. Based on 1H NMR data, the conductivity loss observed after the aging test is mainly related to the piperidinium degradation that took place, probably via ring-opening Hofmann elimination, alkyl spacer scission and nucleophilic substitution reactions as well. The synthesized AEMs were also tested in an alkaline water electrolysis cell. Piperidinium-based AEM showed superior performance compared to its pyrrolidinium analogue, owing to its higher conductivity as revealed by EIS data, further confirming the ex situ conductivity measurements.

Zirconium based metal-organic framework as highly efficient and acid-stable adsorbent for the rapid removal of Sr2+ and Cs+ from solution

Herein we present acid stable [Zr6(µ3-O)4(µ3-OH)4(OBA)4(OH)3(H2O)3(Me2NH2)]n (OBA = 4,4-oxy bis(benzoic acid)) (Zr(OBA) MOF) with the presence of cationic dimethyl ammonium groups were charge balanced with anionic Zr(OBA)nn– that is effective for removing Sr2+ and Cs+. This MOF shows distribution coefficients and record-high absorption capacities (Qm) of 353 mg/g for Sr2+ and 432.91 mg/g for Cs+ at pH 4, 112.75 mg/g for Sr2+ and 141.24 mg/g for Cs+ under 4 M HNO3 circumstances, and 221.5 mg/g for Sr2+ and 253.77 mg/g for Cs+ from simulated seawater. It was demonstrated that a significant excess of complex cations had no substantial influence on the removal of Sr2+ and Cs+ from simulated seawater and nuclear waste, which have been included with Sr2+ and Cs+. The Langmuir isotherm was well suited for Sr2+ and Cs+ adsorption onto MOF, confirming the existence of monolayer adsorption. This finding was made possible by investigating the Langmuir, Freundlich, and Temkin adsorption isotherms. The results of the experiments agree very well with pseudo-second-order kinetic studies, which leads one to believe that chemisorption is the primary mechanism. The measurement of zeta potential has indicated an electrostatic connection between the negatively charged surface of the MOF and positively charged Sr2+/Cs+ at various pH values. This interaction demonstrates that the adsorption capacity is relatively high. SEM-EDS elemental mapping, IR, and XPS analysis confirm the presence of Sr2+ and Cs+ on MOF - of Zr(OBA)@Sr and Zr(OBA)@Cs MOF after adsorption studies. Sr2+/Cs+ exchanged MOF were improved in order to get a clear image of the ion exchange process, and the binding energies of −87.31 for Zr(OBA)@Sr and −113.75 kJ/mol for Zr(OBA)@Cs, respectively. The dose, initial concentration of metal ions, pH solution, contact time, and other ions of Na+, K+, Ca2+, and Mg2+ that were already present affected the adsorption of Sr2+ and Cs+. Recycle studies of Zr(OBA) MOF show 80 % recovery of Sr2+ and Cs+ even after eight cycles.

Trace Organic Contaminant Removal from Municipal Wastewater by Styrenic β-Cyclodextrin Polymers.

Trace organic contaminants (TrOCs) present major removal challenges for wastewater treatment. TrOCs, such as perfluoroalkyl and polyfluoroalkyl substances (PFAS), are associated with chronic toxicity at ng L-1 exposure levels and should be removed from wastewater to enable safe reuse and release of treated effluents. Established adsorbents, such as granular activated carbon (GAC), exhibit variable TrOC removal and fouling by wastewater constituents. These shortcomings motivate the development of selective novel adsorbents that also maintain robust performance in wastewater. Cross-linked β-cyclodextrin (β-CD) polymers are promising adsorbents with demonstrated TrOC removal efficacy. Here, we report a simplified and potentially scalable synthesis of a porous polymer composed of styrene-linked β-CD and cationic ammonium groups. Batch adsorption experiments demonstrate that the polymer is a selective adsorbent exhibiting complete removal for six out of 13 contaminants with less adsorption inhibition than GAC in wastewater. The polymer also exhibits faster adsorption kinetics than GAC and ion exchange (IX) resin, higher adsorption affinity for PFAS than GAC, and is regenerable by solvent wash. Rapid small-scale column tests show that the polymer exhibits later breakthrough times compared to GAC and IX resin. These results demonstrate the potential for β-CD polymers to remediate TrOCs from complex water matrices.

Constructing a Photothermal and Quaternary Ammonium Cation Bactericidal Platform onto SEBS for Synergistic Therapy.

Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) with eminent elasticity, thermoplastic ability, and biological stability has aroused great interest in the medical area. However, bacteria can easily adhere to the hydrophobic SEBS surface to cause medical device-related infections. In this work, SEBS is modified to prepare the SEBS-polydopamine (PDA)-poly(lysine) quaternary ammonium derivative (PLQ) antibacterial surface by PDA deposition and surface grafting techniques to solve bacterial infections. PDA is used as an intermediate layer and presents an excellent photothermal effect. The grafted polymer PLQ has antimicrobial quaternary ammonium cation groups, which plays synergistic bactericidal therapy with PDA. The SEBS-PDA-PLQ surface almost totally suppresses the growth of bacteria with a surface bacterial survival rate of 0.05% under laser irradiation. The outstanding antibacterial activity of the SEBS-PDA-PLQ surface is attributed to the synergistic effects of the photothermal performance of PDA and quaternary ammonium cationic functional groups of PLQ. In addition, the membrane SEBS-PDA-PLQ shows good hydrophilicity, antiprotein adsorption ability, chemical stability, and biocompatibility. This antibiotic-free antimicrobial approach has great potential for practical application in solving infections associated with medical devices.

A Delayed Cross‐Linking Strategy for Evolvable Hydrogels

AbstractBiological tissues grow or evolve through a series of complicated processes of matter and energy internalization, which are highly challenging to mimic in synthetic materials. Herein, a delayed cross‐linking strategy is developed to program the reactivity of cross‐linking sites and make hydrogels evolvable. The polymer networks are constructed by combining polyvinyl alcohol (PVA) with a polyzwitterion comprising both cationic quaternary ammonium and anionic phenylboronic acid groups (PQBA). Shielding of phenylboronic acid groups in ion pairs and polyzwitterion microdomains delays the cross‐linking between PVA and PQBA. Mechanical stimulations unlock the phenylboronic acid groups and dramatically accelerate the cross‐linking reaction. A simple stretching treatment makes the hydrogels stronger. Training the hydrogels with five cycles of 200% stretching results in up to ≈13.0‐ and ≈22.8‐fold of enhancements in tensile strength and maximum Young's modulus, respectively. The hydrogels can also self‐evolve in a damage‐healing process, the fracture strength and maximum Young's modulus of the hydrogels increase by at most ≈7.5‐ and ≈27.2‐fold after five times of repeated tensile rupture and self‐healing. The study demonstrates the possibility of designing “living polymeric materials” by programming the cross‐linking kinetics of polymer networks.

Ketorolac Tromethamine Loaded Nano-Spray Dried Nanoparticles: Preparation, Characterization, Cell Viability, COL1A1 Gene Simulation and Determination of Anti-inflammatory Activity by In vivo HET-CAM Assay.

Ketorolac tromethamine (KT) is a non-steroidal anti-inflammatory drug from the heteroaryl acetic acid derivatives family. The most widely used new nanotechnological approaches for topical drug delivery are polymeric nanoparticles (NPs). Successful results have been obtained with low doses in many treatments, such as cancer, antimicrobial, pain, made with nanoparticle formulations of drug active ingredients. NPs were prepared using Nano Spray-Dryer. The cytotoxicity of the optimum formulation in BJ (ATCC® CRL-2522™) human fibroblast cells was determined by the WST- 1 method and the gene activity was elucidated by mRNA isolation and real-time polymerase chain reaction (RT-PCR). The in vivo HET- CAM assay was performed for anti-inflammatory activity. NPs presented PDI values lower than 0.5, and therefore particle size distribution was decided to be monodisperse. Positive zeta potential values of NPs highlighted the presence of the cationic ammonium group of Eudragit® RS 100. The release rates observed from KT-NP coded formulations after 24 hours were 78.4% ± 2.9, demonstrating extended release from all formulations, relative to pure KT. The lowest concentration of KT-NP increased fibroblast cell proliferation higher than the highest concentration of KT. The 5-fold increased effect of KT-NP formulation on collagen gene expression compared to KT is also related to the enhanced anti-inflammatory effect in line with the in vivo HET-CAM assay results. With the obtained cell viability, gene expression, and HET-CAM results, it has the hope of a successful nano-topical formulation, especially in both wound healing and anti-inflammatory treatment.

Preparation of Water-Soluble Polyion Complex (PIC) Micelles with Random Copolymers Containing Pendant Quaternary Ammonium and Sulfonate Groups.

Cationic random copolymers (PCm) consisting of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC; P) with methacroylcholine chloride (MCC; C) and anionic random copolymers (PSn) consisting of MPC and potassium 3-(methacryloyloxy)propanesulfonate (MPS; S) were prepared via a reversible addition-fragmentation chain transfer method. "m" and "n" represent the compositions (mol %) of the MCC and MPS units in the copolymers, respectively. The degrees of polymerization for the copolymers were 93-99. Water-soluble MPC unit contains a pendant zwitterionic phosphorylcholine group whose charges are neutralized in pendant groups. MCC and MPS units contain the cationic quaternary ammonium and anionic sulfonate groups, respectively. The stoichiometrically charge-neutralized mixture of a matched pair of PCm and PSn aqueous solutions resulted in the spontaneous formation of water-soluble PCm/PSn polyion complex (PIC) micelles. These PIC micelles have the MPC-rich surface and MCC/MPS core. These PIC micelles were characterized using 1H NMR, dynamic and static light scattering, and transmission electron microscopic measurements. The hydrodynamic radius of these PIC micelles depends on the mixing ratio of the oppositely charged random copolymers. The charge-neutralized mixture formed maximum-size PIC micelles.

Decatungstate-Catalyzed C(sp3)–H Alkylation of a Val Residue Proximal to the N-Terminus Controlled by an Electrostatic Interaction

The decatungstate photocatalyst [W10O32]4- efficiently promoted the C(sp3)-H alkylation of the trifluoroacetic acid salt of valine methyl ester (H-Val-OMe·TFA) with electron-deficient alkenes under UV irradiation. The electrostatic interaction between the cationic ammonium group (+NH3) of the main chain and anionic [W10O32]4- played an important role in this reaction. The influence of various protected amino acids in the C(sp3)-H alkylation was investigated as the model reaction for the alkylation of Val-containing peptides. The introduction of an alkyne moiety into Val through this alkylation was successful, and successive copper-catalyzed azide-alkyne cycloaddition (CuAAC) was demonstrated. The C(sp3)-H bond of a Val residue located at the second from the N-terminus was also successfully converted. C(sp3)-H alkylation of oligopeptides containing two Val residues selectively proceeded proximally to the N-terminus.

Design of novel polyurethane-based ionene nanocarriers for cancer therapy: Synthesis, in-vitro, and in-vivo studies

New strategies for constructing versatile nanocarriers are needed for cancer therapy to overcome the multiple challenges of targeted delivery. This work explores the advantages of polyurethane with main-chain quaternary ammonium salt moieties (ionene) as a novel carrier for targeted drug delivery. We have developed a novel cationic soybean oil-based polyurethane ionene nanocarrier (CPUI) that can act as an effective anticancer agent and efficiently deliver the anticancer drug 5-fluorouracil (5FU). We also report a potential anticancer drug delivery system targeting the folate receptor. In vitro experiments with blank CPUI carriers on the 4T1 (mouse breast cancer cell line) and the NIH-3T3 (mouse fibroblast cell line) revealed high cytotoxicity for the cancer cells but only low cytotoxicity for the normal fibroblast cells. The CPUI nanoparticles were readily loaded with 5FU (5FU-CPUI) in water using electrostatic interactions between the cationic quaternary ammonium groups of ionene and the anionic 5FU. The in vivo study in mice with tumors showed that the blank CPUI carriers significantly inhibited tumor growth, even more than the free drug (5FU). The inhibitory effect on tumor growth was slightly enhanced when the carriers were loaded with 5FU. The prepared nanoparticles had a high loading capacity of 41.8 %. Further enhancement of the inhibitory effect was observed when folic acid (FA) was added as a targeting moiety to the system via ion exchange with the bromine counterion of the quaternary ammonium moieties. The results suggest that the efficacy of FA-CPUI-5FU nanoparticles as vehicles for drug delivery can be enhanced via folate receptor (FR) mediated endocytosis in 4T1 cells and these novel nanocarriers may provide a potential platform for effective targeted drug delivery to tumor tissue and breast cancer therapy in the clinic.

Pendant Length-Dependent Electrochemical Performances for Conjugated Organic Polymers as Solid-State Polymer Electrolytes in Lithium Metal Batteries.

The development of solid-state polymer electrolytes (SPEs) has been plagued by poor ionic conductivity, low ionic transference number, and limited electrochemical potential window. The exploitation of ionized SPEs is a feasible avenue to solve this problem. Herein, conjugated organic polymers (COPs) with excellent designability and rich pore structures have been selected as platforms for exploration. Three cationic COPs with different chain lengths of quaternary ammonium salts (CbzT@Cx, x = 4, 6, 9) are designed and applied to SPEs for the first time. Meanwhile, the effects of chain lengths on their electrochemical performances are compared. Especially, CbzT@C9 shows the most attractive electrochemical performance due to its high specific surface area of 212.3 m2 g-1. The larger specific surface area allows more exposure of the long-chain quaternary ammonium cation groups, which is more favorable for the dissociation of lithium salts. Moreover, the flexible long-chain structure increases the compatibility with poly(ethylene oxide) (PEO) and reduces the crystallinity of PEO to some extent. The richer pore structure can accommodate more PEO, further disrupting the crystallinity of PEO and creating more channels for the ether-oxygen chain to transport lithium ions. At 60 °C, the SPE (CbzTM@C9) presents an excellent ionic conductivity (σ) of 8.00 × 10-4 S cm-1. CbzTM@C9 has a lithium-ion transference number (tLi+) of 0.48. Thus, the assembled Li/CbzTM@C9/LiFePO4 battery provides a good discharge capacity of 158.8 mAh g-1 at 0.1C. After 70 cycles, the capacity retention rate is 93.8% with a Coulombic efficiency of 98%. The excellent flexibility brings stable power supply capability under various bending angles to the assembled Li/CbzTM@C9/LiFePO4 soft-packed battery. The project uses conjugated organic polymers in SPEs and creates an avenue to develop flexible energy storage equipment.

Alkaline Stability of Anion-Exchange Membranes.

Recently, the development of durable anion-exchange membrane fuel cells (AEMFCs) has increased in intensity due to their potential to use low-cost, sustainable components. However, the decomposition of the quaternary ammonium (QA) cationic groups in the anion-exchange membranes (AEMs) during cell operation is still a major challenge. Many different QA types and functionalized polymers have been proposed that achieve high AEM stabilities in strongly alkaline aqueous solutions. We previously developed an ex situ technique to measure AEM alkaline stabilities in an environment that simulates the low-hydration conditions in an operating AEMFC. However, this method required the AEMs to be soluble in DMSO solvent, so decomposition could be monitored using 1H nuclear magnetic resonance (NMR). We now report the extension of this ex situ protocol to spectroscopically measure the alkaline stability of insoluble AEMs. The stability ofradiation-grafted (RG) poly(ethylene-co-tetrafluoroethylene)-(ETFE)-based poly(vinylbenzyltrimethylammonium) (ETFE-TMA) and poly(vinylbenzyltriethylammonium) (ETFE-TEA) AEMs were studied using Raman spectroscopy alongside changes in their true OH- conductivities and ion-exchange capacities (IEC). A crosslinked polymer made from poly(styrene-co-vinylbenzyl chloride) random copolymer and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA) was also studied. The results are consistent with our previous studies based on QA-type model small molecules and soluble poly(2,6-dimethylphenylene oxide) (PPO) polymers. Our work presents a reliable ex situ technique to measure the true alkaline stability of AEMs for fuel cells and water electrolyzers.

Efficient removal of short-chain and long-chain PFAS by cationic nanocellulose

Quaternized nanocellulose (QNC), synthesized in this study, showed improved removal of both short chain and long chain PFAS by increasing the electrostatic interactions between the anionic functional groups of PFAS and the cationic quaternary ammonium groups of QNC.

Arylene Diimide Derivatives as Anolyte Materials with Two-Electron Storage for Ultrastable Neutral Aqueous Organic Redox Flow Batteries

Arylene Diimide Derivatives as Anolyte Materials with Two-Electron Storage for Ultrastable Neutral Aqueous Organic Redox Flow Batteries