Imidazolium Polymer Research Articles

Structural engineering of antimicrobials for optimal broad-spectrum activity

Antimicrobial materials are a crucial component in eradicating and managing the spread of infectious diseases. They are expected to act on a broad-spectrum of microbes, including emerging pathogens which could cause the next Disease X. Herein, we reassessed a series of antimicrobial imidazolium polymers on our shelves and uncovered extended functionality through dual modes of action. By redesigning their structures, a truly broad-spectrum antimicrobial material with optimized activity against bacteria (G ​+ve, G -ve) and fungi, as well as enveloped and non-enveloped viruses was developed. We demonstrated that the imidazolium polymer exhibits dual modes of function against microbes: targeting the microbial membrane and binding DNA. The latter DNA binding affinity was found to be key against non-enveloped viruses. With this insight, we designed small molecule compounds that exhibited optimum broad-spectrum antimicrobial activity and excellent efficacy against ESKAPE group of pathogens that are responsible for some of the deadliest nosocomial infections worldwide. Our results could also shed light on the design of broad-spectrum antimicrobial compounds against Disease X.

Introduction of Al(III)‐Ion‐Based Solid Polymer Electrolyte Material for Energy Storage Device Applications

AbstractSolid phase electrolyte system PVIm‐R‐PEG‐AlCl3 is introduced for Al(III) ion‐based energy storage material. Here, we introduced [AlCl3Br]− counter anion system with N‐octyl‐polyvinyl imidazolium polymer matrix supported by PEG. Electrolyte material shows good thermal stability with a Glass transition temperature (Tg~148 °C), which provides a good working temperature range for material processing. PVIm‐R‐PEG‐AlCl3 shows electrochemical stability of 1.5 V and red‐ox properties, it has 96 % of ionic conduction against the Al metal. The conductivity of electrolyte material is found in the range of 10−5 S/cm at room temperatures and 10−4 S/cm at higher temperature (>40 °C). The polymer electrolyte matrix shows the mobility of 1.37×10−6 m2/Vs and drift ionic velocity of 3.42×10−4 m/s at 30 °C. The ionic movement of Al(III) ions inside the matrix follows correlated type hopping with the activation energy of 0.266 eV. This Al(III) ion‐based solid polymer electrolyte (SPE) is associated with a large amount of capacitance with a tiny electrode contribution.

Smart elastomer sanitizer with chemically bonded active compound and on‐demand‐release antimicrobial functionalities

AbstractHand or surface sanitizers are all liquid‐based products which can be mainly categorized as alcohol or non‐alcohol based. The constant release of highly persistent disinfectants and chemicals is hazardous to the environment and human health. Herein, a new concept of solid elastomer sanitizer with inherent fast‐killing antimicrobial property is described. Silicone (PDMS) was chosen as the elastomer where the active antimicrobial component of imidazolium polymer (PIM) was carefully modified and incorporated into the PDMS matrix through strong covalent bonds. This chemically bonded antimicrobial component within PDMS acts via release‐on‐demand model which allows for the long‐term reusability of the material. The resulting material can serve as a reusable solid sanitizer that is toxic‐free and skin‐friendly with fast‐killing property. It was proven to sanitize our hands or surfaces and kill microbes within 30–60 s of contact, including ESKAPE pathogens, bacteria, fungi and MS2 bacteriophage. This new concept of solid sanitizer methodology will provide an interesting insight and infinite possibilities for extending to other types of elastomers with suitable or tunable antimicrobial components. This also helps to provide a safer and greener sanitizing model which can dramatically reduce the usage and/or release of disinfectants or harmful chemicals to the environment. The possibilities of extending to other elastomers also widen its potential applications.

Unraveling energy storage behavior of independent ions in carbon electrode for supercapacitors by polymeric ionic liquids and electrochemical quartz crystal microbalance

A fundamental understanding of the charge storage mechanism of electrochemical double-layer capacitors (EDLCs) requires an in-depth storage behavior investigation of independent ions (individual cations or anions) on the electrode surface. The direct in-situ observation for energy storage behavior of individual ions under realistic conditions remains challenge. Herein, in-situ monitoring the energy storage behavior of independent ions is realized with assistance of polymeric ionic liquids skillfully. Triangle cyclic voltammogram (CV) curves indicate that polymeric imidazole cations PVBIm+ with huge size cannot enter the active carbon pores upon charging, whereas only free anions can. The CV and electrochemical quartz crystal microbalance (EQCM) simultaneously detect ion adsorption/desorption during charging. It’s proposed that ion adsorption/desorption is governed by electrostatic attraction and repulsion of charged particles. PVBIm+ are adsorbed on the electrode surface due to ion adsorption mechanism during the negative polarization and have a small capacity contribution. Free anions contribute capacitance, their number entering the pore is determined by the interaction between polycaions and anions. Moreover, PVBIm(0.1)+ with higher polymerization degree may promote desorption of polycations and prevent further adsorption of anions at higher potential in positive polarization. This work not only observes the charging behavior of independent ions, but also reveals the relevant charging mechanism through EQCM, paving the way for panorama of EDLC.

High-voltage electrochemical double layer capacitors enabled by polymeric ionic liquid

Improving the energy density of electrochemical double layer capacitors (EDLC) is an important but challenging research topic. Electrolytes with wide operating potential windows are key materials for current EDLC technology. In this work, an ether branch polymeric imidazole ionic liquid (PVEIm.TFSI) is synsthesized and served as an electrolyte additive in common electrolyte to optimize the working potential ranges of carbon-based EDLC. The addition of PVEIm.TFSI can improve the electrochemical stability of electrolytes and effectively adjust the upper limit potential (PU), lower limit potential (PL). Under the optimal addition ratio of 10%, the operational voltage of EDLC increases from 2.8 V to 3.2 V, which lead to an approximately 41.5% energy density increase compared with EDLC without additive. Cycling stabibity of EDLC containing 10% PVEIm.TFSI is significantly enhanced under both 3.0 V and 3.2 V. Furthermore, an equivalent circuit model and Bode plots are proposed from the electrochemical impedance spectroscopy (EIS) measurements. Both simulated and measured date dedicate that PVEIm.TFSI reduces each element of resistance, which result in more ions movement and smaller energy barrier for the diffusion processes, thereby improving the electrochemical performance of cells.

Fabrication of modified PVDF membrane in the presence of PVI polymer and evaluation of its performance in the filtration process

In this research, to prepare a polymer membrane with hydrophilic nature that has anti-fouling and anti-adhesion properties first, polyvinyl imidazole (PVI) Polymer was bonded as a surface modifier of fluorinated polyvinylidene (PVDF) membranes by Atom transfer radical polymerization (ATRP) method. Therefore, to confirm the chemical changes of the hydrophilic membrane surface such as PVI polymer chain bonding and to investigate the uniform distribution of the polymer in the modified membrane pores and surface, experiments such as attenuated general reflectance (ATR-FTIR), nuclear magnetic resonance (H-NMR), Water contact angle (WCA) and scanning electron microscopy (SEM), zeta potential, Atomic force microscopy (AFM) spectroscopy, Thermo-gravimetric analysis (TGA), X-ray energy scattering (EDX), X-ray diffraction (XRD) patterns were performed. The results showed that the WCA for M1 membrane was about 83.37 ± 1.77 and Mb6 membrane was about 35.45 ± 1.45, which improved the WCA rate of Mb6 membrane surface by about 57.10%.Therefore, the total Anti-fouling rate and Flux recovery ratio (FRR) and rejection oil rate increased by about 35.2%, 18.65% and 10%, respectively. This study aimed to investigate the surface modification of membranes prepared with hydrophilic polymer PVI to separate oil from the oil-in-water emulsion, which is a suitable method and potential approach in controlling large-volume oil-in-water emulsion effluents.

Ultra-stable 2D cuprofullerene imidazolate polymer as a high-performance visible-light photodetector

本工作通过溶剂热法制备了一种超稳定二维层状铜(I)富勒 烯配位聚合物材料. Cu-(η2-C60)配位作用和层间凹凸π⋅⋅⋅π相互作用 支撑C60分子排列形成倾斜六方面堆积((i-hfp))特点, 显著地改善了 材料的化学稳定性. 该材料表现出高性能可见光探测功能. 密度泛 函计算表明, 与六方紧密堆积和立方堆积的C60纳米材料类似, 其优 异的光探测功能主要来源于C60分子本身, 但是铜(I)的配位显著增 强了其对可见光的吸收效率, 改善了材料的可见光探测功能. 该工 作对于拓展富勒烯光电功能材料的种类具有重要意义.

A spirobifluorene-based water-soluble imidazolium polymer for luminescence sensing

A water-soluble luminescent sensor based on a spirobifluorene-based imidazolium polymer is developed for the selective sensing of Fe3+ and Cr2O72−.

Synthesis of propylene glycol methyl ether catalyzed by imidazole polymer catalyst: Performance evaluation, kinetics study, and process simulation

An imidazole polymer (divinylbenzene-vinylimidazole) catalyst (P-DVB-VIM) was developed for production of the eco-friendly solvent propylene glycol methyl ether (PGME) by the propoxylation reaction of propylene oxide (PO) with methanol (ME). The catalyst was characterized in detail by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analysis. 1H NMR was used to characterize the structural features of the catalyst precursor, i.e., the linear polymer of vinylimidazole (PVIM). An “electrophile nucleophile dual activation” ring-opening mechanism was proposed based on the “cooperative effect” of the reactant and PVIM. The catalytic performance was investigated and optimized at 100–130 ℃ using an autoclave batch reactor. The results reveal that the P-DVB-VIM shows excellent catalytic performance, exhibiting the highest turnover frequency (TOF) number at 120 °C within 45 min. The reaction kinetics was systematically studied using the pseudohomogeneous (PH) kinetic model. The kinetic parameters were determined by non-linear regression analysis of the experimental data. Validation of the model showed that the experimental data were in good agreement with the predicted outcomes. Moreover, based on the proposed kinetic model, steady-state simulations of the production of PGME in a fixed-bed reactor were carried out to determine the optimal design parameters, thus providing a useful guide for the design and production of PGME on the industrial scale.

One-Step Assembly of Fluorescence-Based Cyanide Sensors from Inexpensive, Off-The-Shelf Materials.

We report a simple and versatile approach to assemble sensitive and selective fluorescence “turn-on” sensors for cyanide by combining three off-the-shelf materials; namely fluorescent dye, 1-vinyl imidazole polymer, and cupric chloride. The cyanide-sensing species is a non-fluorescent fluorophore-polymer-Cu2+ complex; which forms as a result of the imidazole polymer’s ability to bind both fluorophore and fluorescence quencher (Cu2+). Cyanide removes Cu2+ from these complexes; thereby “turning-on” sensor fluorescence. These sensors are water-soluble and have a detection limit of ~2.5 μM (CN−) in water. Our ternary complex-based sensing approach also enables facile emission tuning; we demonstrate the convenient, synthesis-free preparation of blue and green-emitting sensors using distyrylbiphenyl and fluorescein fluorophores, respectively. Furthermore; these ternary complexes are easily immobilized using agarose to create cyanide-sensing hydrogels; which are then used in a simple; novel microdiffusion apparatus to achieve interference-free cyanide analysis of aqueous media. The present study provides an inexpensive approach for portable; interference-free cyanide detection.

Grafting high content of imidazolium polymer brushes on graphene oxide for nanocomposite membranes with enhanced anion transport

Polymer functionalized nanoparticles have attracted burgeoning interests in designing and fabricating novel nanocomposite membranes for fast transport of ions or small molecules. Herein, imidazolium polymer coated graphene oxides (AImGOs), bearing different length of polymer brushes, are synthesized via ATRP technique, and thus a very high weight percentage of imidazolium polymer brushes on GO (up to 89.5%) is acquired, corresponding to a high IEC value up to 65.5 mmol g−1. The as-synthesized AImGOs are then dispersed into poly(vinyl alcohol) (PVA) to prepare nanocomposite membranes. The polymer brushes coated on AImGOs render better interfacial compatibility and filler dispersity. The large specific surface area and high aspect ratio of GO contributes to the enhancement of swelling resistance and mechanical stability of membranes. More importantly, the imidazolium polymer brushes on AImGOs endow the membrane with efficient OH– conduction ability due to the high loading of OH– hopping sites, the flexible chain, and the intrinsic large surface area of GO, demonstrating that efficient OH−-hopping pathways are constructed along the interface between PVA matrix and AImGO. By lengthening the polymer brushes, increasing AImGO content, and adopting appropriate types of imidazolium cations, a remarkable increment of OH– conductivity are observed. To be noted, long polymer brushes quaternized with ethyl chloroformate yield zwitterion type functionality, entitling the highest OH– conductivity of 31.6 mS cm−1 at 30 °C (100% RH).

Protic Imidazolium Polymer as Ion Conductor for Improved Oxygen Evolution Performance.

Improving the electrocatalytic performance of oxygen evolution reaction (OER) is essential for oxygen-involved electrochemical devices, including water splitting and rechargeable metal–air batteries. In this work, we report that the OER performance of commercial catalysts of IrO2, Co3O4, and Pt-C can be improved by replacing the traditional Nafion® ionomer with newly synthesized copolymers consisting of protonated imidazolium moieties such as ion conductors and binders in electrodes. Specifically, such an improvement in OER performance for all the tested catalysts is more significant in basic and neutral environments than that under acidic conditions. We anticipate that the results will provide new ideas for the conceptual design of electrodes for oxygen-involved electrochemical devices.

Poly(1-vinylimidazole) Prospects in Gene Delivery

Polymeric amines are being studied intensively as components of systems for gene delivery in genetic engineering and gene therapy of genetic disorders, including cancer. Despite remarkable achievements in the field, polymeric amines, such as polyethyleneimine, show some disadvantages. Strong interaction between the amine-containing polymer and nucleic acid hampers the release of nucleic acid in the cell cytoplasm. Amine groups can interact with the cell membrane which results in cell death. These limitations of polymeric amines stimulated an investigation of new structures for gene delivery. Imidazole-containing polymers have attracted attention as lesser basic substances, while they are able to interact with polymeric acids. Further development of imidazole-based gene delivery agents requires knowledge about some fundamental aspects of interaction between nucleic acids, and polymeric imidazoles. In this work, we studied the complexation of poly(1-vinylimidazole) and oligomeric DNA. We found that the number of active sites capable of binding with negatively charged phosphate groups is comparable with the number of protonated imidazole units in the case of high molecular weight polymer. The increase in polymer charge by 1-bromopropane quaternizating 1%−5% imidazole units or by decreasing the pH to 6.5−7 considerably increased the ability of poly(1-vinylimidazole) to interact with oligonucleotides. The pH sensitivity of this interaction is interesting for cancer gene therapy because the tumours have a lowered intercellular pH (stable oligonucleotide complex) and a higher extracellular pH which can lead to complex dissociation. Minimal critical length for complexation of quaternized poly(1-vinylimidazole) and DNA is below eight units which corresponds to polymers with amine groups. Fluorescence-tagged poly(1-vinylimidazole) samples were obtained and their potential for monitoring the polymer and polymer-oligonucleotide complex internalization into living cells was demonstrated.

Electron transfer properties of a redox polyelectrolyte based on ferrocenated imidazolium

We report the characterization of a redox polyelectrolyte based on ferrocenated imidazolium and imidazole repeating units to evaluate the impact of the charged structure on the electron transfer rates. N-vinyl-N′-(methylferrocene)imidazolium chloride monomer was polymerized in the presence of various amounts of vinylimidazole to obtain the electroactive heteropolymer, as the homopolymerization was unsuccessful due to electrostatic repulsion between the imidazolium monomers. NMR was used to determine the ratio of electroactive to neutral monomers in the polymer. The electrochemistry of a thin film of the polymer casted on the surface of glassy carbon electrode was studied in 1 M NaClO4 aqueous electrolyte. Cyclic voltammetry at low scan rates (i.e. ν < 0.1 V s−1) showed a response close to the expected behavior for a surface-confined process without any significant interactions between the ferrocene redox centers, in contrast with poly(vinylferrocene). At high scan rates (ν > 1 V s−1); the behavior was diffusion-controlled. The diffusion coefficient of the ferrocene centers in the imidazolium polymer is 1.7 × 10−9 cm2 s−1 which is one order of magnitude higher than poly(vinylferrocene), and the standard rate constant, determined by the Nicholson's approach, was k0 = 3.8 × 10−4 cm s−1. These high values are explained by favorable interactions of the electrolyte with the charged imidazolium, providing a fast ion diffusion and pairing with ferrocenium. The potential use of this redox polymer in electrochemical systems is demonstrated via the formation of a composite with electrochemically exfoliated graphite to increase polymer loading.

Synthesis of Nanocomposite Based on Poly Methylene-imidazole as Effective Catalyst in Oxidation of Some Hydrocarbones

The polymers derived from heterocyclic rings like imidazole was prepared and supported to produce catalytic active supported catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), H NMR and UV-visible spectroscopy. The catalyst showed high catalytic activity in the oxidation of cyclohexene and cyclopentene under optimized conditions. In this work cyclohexene and cyclopentene were selected as model alkene for determination the capacity of the prepared imidazole polymer catalyst under optimized conditions of temperature and time of reaction. The catalyst could be readily separated from the catalytic system using uploading 3-5 milligrams of Copper(II), Nickel(II) and Cobalte(II) ions with the surface of polymer the conversion them to nano-particle which are identified by x-ray diffraction. For this research, a statistical method called Response Surface Methodology (RSM) has been used to economize the number of experiments and their meaningful interpretation. The effect of metallated polymer with Copper(II), Nickel(II) and Cobalte(II) were taken to increase the efficiency of oxidation. Optimization results for 0.33 mmole cyclohexene and cyclopentene showed that maximum oxidation efficiency 90. % was achieved at the optimum conditions: catalyst amount 350 mg, temperature 70.0, time 3.30 h and oxidant= 5.25 m mole.

Solid phase microextraction method using a novel polystyrene oleic acid imidazole polymer in micropipette tip of syringe system for speciation and determination of antimony in environmental and food samples

A simple, rapid and sensitive solid phase microextraction method was used for the speciation of inorganic antimony (Sb) by using a novel synthesized polymeric material in micropipette tip of syringe system. In present methodology, the specie of Sb (III) made hydrophobic complex with diethyl dithiocarbamate (DDTC) at pH 5.5 and subsequently adsorbed on polystyrene oleic acid imidazole polymer (POIP), whereas Sb(V) did not made complex and adsorbed on the polymer, remained in aqueous solutions. The strategy of multivariate was carried out to screen out the different variables and assessed the optimum values of their experimental values for the extraction efficiency of analyte. Then the analyte was sorbed on the polymer in micropipette tip of syringe system was quantitatively eluted by different types of acids at different levels for 2–6 aspirating/dispensing cycles. The extracted Sb(III) ions with modifiers were directed into the graphite furnace atomic absorption spectrometry for analysis. The limit of detection (LOD), limit of quantification (LOQ) and preconcentration factor (PF) for Sb(III) was found to be 6 ng L−1, 20 ng L−1 and 100. The RSD value was found to be 4.2%. The standard addition method and certified reference materials were checked for accuracy and validity of method. The developed method was effectively applied for the determination of total and inorganic species of Sb(III) and Sb(V) in different types of water samples, whereas only total Sb was determined in acid digested soil, Tuna fish, rice, spinach, black tea, mixed fruit juice and ice tea samples.

Incorporating transition metals (Ta/Co) into nitrogen-doped carbon as counter electrode catalysts for dye-sensitized solar cells

Carbon materials are potential electrode materials in new energy devices such as solar cells, fuel cells, Li-ion batteries, and supercapacitors, because of their distinct advantages including low cost, high surface area, and high electric conductivity. Nitrogen doping can effectively improve the performance of carbon electrode materials, and introducing transition metals into nitrogen-doped carbon is a promising strategy to develop high-performance electrode materials. In the present work, we successfully prepared two kinds of metal-incorporated nitrogen-doped carbon materials (CoNC and Ta/CoNC) by pyrolyzing a cobalt (II) imidazolate polymer followed by ion exchange. The as-prepared Ta/CoNC materials present a better graphite crystal phase and higher Brunauer-Emmett-Teller (BET) specific surface area (421.5 m2/g) than that of CoNC (354.7 m2/g). As counter electrode (CE) materials in I-mediated dye-sensitized solar cells (DSSCs), Ta/CoNC exhibits a superior catalytic activity and electrochemical stability than CoNC, resulting in a high power conversion efficiency (PCE) of 7.96%, which outperforms the level achieved using a Pt electrode (7.19%) in DSSCs. These Ta- and Co-incorporated nitrogen-doped carbon materials are expected to be used in extensive new energy applications, such as biomass, pollution control and hydrogen generation.

Development of Batch and Flow Immobilized Catalytic Systems with High Catalytic Activity and Reusability.

My mission in catalysis research is to develop highly active and reusable supported catalytic systems in terms of fundamental chemistry and industrial application. For this purpose, I developed three types of highly active and reusable supported catalytic systems. The first type involves polymeric base-supported metal catalysts: Novel polymeric imidazole-Pd and Cu complexes were developed that worked at the mol ppm level for a variety of organic transformations. The second involves catalytic membrane-installed microflow reactors: Membranous polymeric palladium and copper complex/nanoparticle catalysts were installed at the center of a microtube to produce novel catalytic membrane-immobilized flow microreactor devices. These catalytic devices mediated a variety of organic transformations to afford the corresponding products in high yield within 1-38 s. The third is a silicon nanowire array-immobilized palladium nanoparticle catalyst. This device promoted a variety of organic transformations as a heterogeneous catalyst. The Mizoroki-Heck reaction proceeded with 280 mol ppb (0.000028 mol%) of the catalyst, affording the corresponding products in high yield.

Surface labeling of enveloped virus with polymeric imidazole ligand-capped quantum dots via the metabolic incorporation of phospholipids into host cells.

We report a general method for the preparation of quantum dot-labeled viruses through a strain-promoted azide-alkyne cycloaddition (SPAAC) reaction. The quantum dot sample was functionalized with methacrylate-based polymeric imidazole ligands (MA-PILs) bearing dibenzocyclooctyne groups. Enveloped measles virus was labeled with azide groups through the metabolic incorporation of a choline analogue into the host cell membrane, and then linked with the modified QDs. The virus retained its infectious ability against host cells after the modification with MA-PIL capped QDs.

Surface engineered gold nanoparticles through highly stable metal–surfactant complexes

Monodispersed Au nanoparticles were synthesized by the reduction of Au-decyltrimethylammonium bromide (Au-DTAB), which was easily prepared via the reaction of HAuCl4 and DTAB. This Au-DTAB complex is highly stable in air and moisture, and suitable for large-scale synthesis of uniform-sized Au nanoparticles. The nanoparticles were characterized by transmission electron microscopy, optical absorption spectrometry, X-ray diffraction, and Fourier Transform infrared spectroscopy. The size of Au nanoparticles was controlled in the range of 5–10nm by changing the concentrations of reducing agent and Au precursor. The resulting Au nanoparticles were transferred to the aqueous phase after surface engineering using multidentate polymeric ligands with multiple imidazole functional groups. Polymeric imidazole ligands (PILs) demonstrated enhanced binding stability with the Au surface, and overcame the disadvantage of multidentate thiol ligand systems which have oxidative cross-linking and the formation of disulfide bonding. The colloidal stability of surface engineered Au nanoparticles with PILs was investigated by dynamic light scattering (DLS) characterization.