Ionic Monomers Research Articles

Linker Independent Regioselective Protonation Triggered Detoxification of Sulfur Mustards with Smart Porous Organic Photopolymer.

The development of efficient metal-free photocatalysts for the generation of reactive oxygen species (ROS) for sulfur mustard (HD) decontamination can play a vital role against the stockpiling of chemical warfare agents (CWAs). Herein, one novel concept is conceived by smartly choosing a specific ionic monomer and a donor tritopic aldehyde, which can trigger linker-independent regioselective protonation/deprotonation in the polymeric backbone. In this context, the newly developed vinylene-linked ionic polymers (TPA/TPD-Ionic) are further explored for visible-light-assisted detoxification of HD simulants. Time-resolved-photoluminescence (TRPL) study reveals the protonation effect in the polymeric backbone by significantly enhancing the life span of photoexcited electrons. In terms of catalytic performance, TPA-Ionic outperformed TPD-Ionic because of its enhanced excitons formation and charge carrier abilities caused by the donor-acceptor (D-A) backbone and protonation effects. Moreover, the formation of singlet oxygen (1 O2 ) species is confirmed via in-situ Electron Spin Resonance (ESR) spectroscopy and density functional theory (DFT) analysis, which explained the crucial role of solvents in the reaction medium to regulate the (1 O2 ) formation. This study creates a new avenue for developing novel porous photocatalysts and highlights the crucial roles of sacrificial electron donors and solvents in the reaction medium to establish the structure-activity relationship.

One-pot efficient fixation of low-concentration CO2 into cyclic carbonate by mesoporous pyridine-functionalized binuclear poly(ionic liquid)s

The direct conversion of low-concentration CO2 from flue gas avoids the energy-intensive purification and concentration of CO2 to implement the next utilization, making it undoubtedly a green process. However, achieving low-concentration CO2 cycloaddition with epoxide over functional poly(ionic liquid) catalysts and understanding the relevant mechanism at the molecular level is still challenging. Here, novel mesoporous pyridine-functionalized binuclear poly(ionic liquid)s (PB-PIL)s were successfully synthesized by the polymerization of DVB, basic monomers, and binuclear ionic liquid monomers, regulating the density of pyridine sites and binuclear halogen counterions to achieve the optimum balance between the active sites and pore structure of copolymerized materials. Remarkably, PB-PILs were active in the cycloaddition reaction of the low-concentration CO2 (15% CO2 + 85% N2) without any co-catalyst and gave a 95% yield of cyclic carbonate. Relied on DFT theoretical calculation, the activation degree of pyridine to CO2 and the promotion of CO2 insertion were deeply explored, providing more broad ideas for the conversion of low-concentration CO2.

One‐Step Synthesis of Biphasic, Cavity‐forming Polymer Particles via Dispersion Copolymerization of Styrene and Sulfobetaine Methacrylate

Front Cover: Article 2200873 by Laura C. Bradley and co-workers demonstrates the one-step synthesis of biphasic polymer particles using styrene and sulfobetaine methacrylate. The resulting core-shell particles can be transformed, by washing them with water, into particles with internal cavities. Results indicate that differences in monomer solubility can be exploited to control the formation of phase-separated particle morphology when copolymerizing either ionic or zwitterionic monomers with styrene.

Outer‐Shell Self‐Supported Nickel Catalysts for the Synthesis of Polyolefin Composites

AbstractIn situ heterogeneous olefin polymerization has attracted much attention for the synthesis of polyolefin composites. However, the complicated syntheses of specially designed catalysts or the detrimental effects of interactions between catalyst and solid supports pose great challenges. In this contribution, an outer‐shell self‐supporting strategy was designed to heterogenize nickel catalysts on different fillers via precipitation homopolymerization of ionic cluster type polar monomer. These catalysts demonstrated high activity, good product morphology control, and stable performances in ethylene polymerization and copolymerization. Moreover, various polyolefin composites with great mechanical and customized properties can be efficiently synthesized.

Outer-Shell Self-Supported Nickel Catalysts for the Synthesis of Polyolefin Composites.

In situ heterogeneous olefin polymerization has attracted much attention for the synthesis of polyolefin composites. However, the complicated syntheses of specially designed catalysts or the detrimental effects of interactions between catalyst and solid supports pose great challenges. In this contribution, an outer-shell self-supporting strategy was designed to heterogenize nickel catalysts on different fillers via precipitation homopolymerization of ionic cluster type polar monomer. These catalysts demonstrated high activity, good product morphology control, and stable performances in ethylene polymerization and copolymerization. Moreover, various polyolefin composites with great mechanical and customized properties can be efficiently synthesized.

Fabrication of Swellable Organic-Inorganic Hybrid Polymers for CO2-Assisted Hydration of Propylene Epoxide.

Swelling is a very common phenomenon in organic substances. However, the swelling behaviors of inorganic substances had rarely been reported. In this study, a new type of swellable organic-inorganic hybrid polymer (PIL@CHT) was designed and successfully synthesized through free-radical copolymerization of polymerizable phosphonium ionic liquid monomer and vinyl-functionalized hydrotalcite (CHT). The swelling behaviors of PIL@CHT in various solvents with a wide range of Hansen solubility parameters (δT) were investigated, and PIL@CHT exhibited excellent swellable capacity in the solvents with δT > 24.4 MPa1/2. The swollen state of the hybrid PIL@CHT in water presented a network structure with a diameter of approximately 8-12 μm, and CHT particles were well dispersed to the channel of PIL. PIL@CHT was applied to catalyze the CO2-assisted hydration of propylene oxide (PO), in which a cascade reaction including the cycloaddition of CO2 and PO and the subsequent hydrolysis of propylene carbonate (PC) occurred. PIL@CHT, combining the active sites of PIL and CHT, synergistically catalyzed this cascade reaction and achieved a high yield (93.0%) and selectivity (98.2%) of 1,2-propanediol (1,2-MPG) under a low H2O/PO ratio of 1.5/1. Moreover, the catalyst could be recycled seven times without any significant loss of catalytic activities and had good substrate generality.

Reducing dielectric confinement effect in ionic covalent organic nanosheets to promote the visible-light-driven hydrogen evolution

Ultra-thin two-dimensional (2D) organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture. Nonetheless, the inherent dielectric confinement of 2D materials will induce a strong exciton effect hampering the charge separation. Herein, we demonstrated an effective way to reduce the dielectric confinement effect of 2D ionic covalent organic nanosheets (iCONs) by tailoring the functional group via molecular engineering. Three ultra-thin CONs with different functional groups and the same ionic moieties were synthesized through Schiff base condensation between ionic amino monomer triaminoguanidinium chloride (TG) and aldehyde linkers. The integration of the hydroxyl group was found to significantly increase the dielectric constant by enhancing the polarizability of ionic moieties, and thus reduced the dielectric confinement and the corresponding exciton binding energy (Eb). The champion hydroxyl-functional iCON exhibited promoted exciton dissociation and in turn a high photocatalytic hydrogen production rate under visible-light irradiation. This work provided insights into the rationalization of the dielectric confinement effect of low-dimensional photocatalysts.

Environmentally Adaptable Organo-Ionic Gel-Based Electrodes for Real-Time On-Skin Electrocardiography Monitoring.

On-skin personal electrocardiography (ECG) devices, which can monitor real-time cardiac autonomic changes, have been widely applied to predict cardiac diseases and save lives. However, current interface electrodes fail to be unconditionally and universally applicable, often losing their efficiency and functionality under harsh atmospheric conditions (e.g., underwater, abnormal temperature, and humidity). Herein, an environmentally adaptable organo-ionic gel-based electrode (OIGE) is developed with a facile one-pot synthesis of highly conductive choline-based ionic liquid ([DMAEA-Q] [TFSI], I.L.) and monomers (2,2,2-trifluoroethyl acrylate (TFEA) and N-hydroxyethyl acrylamide (HEAA). In virtue of inherent conductivity, self-responsive hydrophobic barriers, dual-solvent effect, and multiple interfacial interactions, this OIGE features distinct sweat and water-resistance, anti-freezing and anti-dehydration properties with strong adhesiveness and electrical stability under all kinds of circumstances. In contrast to the dysfunction of commercial gel electrodes (CGEs), this OIGE with stronger adhesion as well as skin tolerability can realize a real-time and accurate collection of ECG signals under multiple extreme conditions, including aquatic environments (sweat and underwater), cryogenic (<-20°C) and arid (dehydration) environments. Therefore, the OIGE shows great prospects in diagnosing cardiovascular diseases and paves new horizons for multi-harsh environmental personalizedhealthcare.

Design of Synthetic Hydrogel Compositions for Noncovalent Protein Recognition.

Multifunctional hydrogels composed of segments with ionizable, hydrophilic, and hydrophobic monomers have been optimized for sensing, bioseparation, and therapeutic applications. While the "biological identity" of bound proteins from biofluids underlies device performance in each context, design rules that predict protein binding outcomes from hydrogel design parameters are lacking. Uniquely, hydrogel designs that influence protein affinity (e.g., ionizable monomers, hydrophobic moieties, conjugated ligands, cross-linking) also affect physical properties (e.g., matrix stiffness, volumetric swelling). Here, we evaluated the influence of hydrophobic comonomer steric bulk and quantity on the protein recognition characteristics of ionizable microscale hydrogels (microgels) while controlling for swelling. Using a library synthesis approach, we identified compositions that balance the practical balance between protein-microgel affinity and the loaded mass at saturation. Intermediate quantities (10-30 mol %) of hydrophobic comonomer increased the equilibrium binding of certain model proteins (lysozyme, lactoferrin) in buffer conditions that favored complementary electrostatic interactions. Solvent-accessible surface area analysis of model proteins identified arginine content as highly predictive of model proteins' binding to our library of hydrogels containing acidic and hydrophobic comonomers. Taken together, we established an empirical framework for characterizing the molecular recognition properties of multifunctional hydrogels. Our study is the first to identify solvent-accessible arginine as an important predictor for protein binding to hydrogels containing both acidic and hydrophobic subunits.

A Highly Ion‐Conductive Solid Polymer Electrolyte with Good Thermal Stability and Nonflammability for All‐Solid‐State Li Metal Batteries

Lithium metal batteries (LMBs) have been recognized as one of the most promising energy storage devices due to their high energy density. The leakage, corrosion to Li metal anode, and flammability of organic liquid electrolytes bring great security problems for LMBs. Polymeric ionic liquid (PIL)‐based solid polymer electrolytes (SPE), possessing nonflammability, excellent thermal, chemical, electrochemical stability, are a kind of promising SPE for highly safe all‐solid‐state LMBs. Nevertheless, the low ambient conductivity of pristine PIL‐based SPE restricts their application in solid‐state LMBs. Herein, an ionic liquid monomer (denoted as GIM) is designed and synthesized and copolymerized with vinyl ethylene carbonate (VEC) monomer by UV‐light curing to prepare P(GIM‐VEC) SPE. The prepared P(GIM‐VEC) SPE is thermally stable and intrinsically nonflammable, possesses high ambient ionic conductivity, and can suppress lithium dendrite growth and stabilize the solid electrolyte interface. Thus, the resultant all‐solid‐state LiFePO4 (LFP)|P(GIM‐VEC)|Li battery exhibits a high initial discharge capacity of 152.7 mAh g−1 at 0.1 C along with a good stability and rate capability at room temperature. Herein, new guidance is provided for developing ambient workable SPEs with high ionic conductivity, nonflammability, and excellent thermal stability for all‐solid‐state Li metal batteries.

Construction of Aluminum‐Porphyrin‐Based Hypercrosslinked Ionic Polymers (HIPs) by Direct Knitting Approach for CO2 Capture and In‐Situ Conversion to Cyclic Carbonates

AbstractHypercrosslinked polymers (HCPs) constructed by Friedel‐Crafts reaction have drawn increasing attention in recent decades, but their multifunctionalization remains a huge challenge. Herein, a series of aluminum‐porphyrin‐based hypercrosslinked ionic polymers have been successfully synthesized by direct knitting approach without additional electrophilic comonomers, which involves the copolymerization of neutral porphyrin monomers and ionic building. By increasing the connected nodes numbers of ionic monomers, the introduction of abundant tetraphenylmethane fragements into the porphyrin backbones endows them with high‐density ionic active sites. Accordingly, the well‐matched molar ratios of aluminum sites to nucleophilic chloride anions that work synergistically for CO2/epoxide coupling can be achieved. Al‐HIP‐2 with flexible ionic pendants and a high Al/Cl ratio allows CO2 cycloaddition to be performed at ambient conditions or with diluted CO2; while Al‐HIP‐3 with rigid ionic moieties and a relatively low Al/Cl ratio exhibits higher specific surface area and stronger CO2 capture ability. Therefore, this co‐condensation strategy provides a simple and feasible pathway for adjusting the reactivity ratios of comonomers via simple structural changes in the knitting process, thus achieving the rational construction of multifunctionalized HCPs for CO2 capture and in‐situ conversion to cyclic carbonates.

Conjugate acid-base bi-functional polymeric ionic liquids (CAB-PILs) as efficient catalysts for CO2 capture and subsequent glycidol cycloaddition reaction

Conjugate acid-base bi-functional PILs (CAB-PILs) with carboxylate and carboxyl branches were synthesized and used as catalysts for the cycloaddition reaction of glycidol with CO2. Two functional ionic monomers, 3-(carboxymethyl)-1-vinyl-1H-imidazol-3-ium chloride (CEImCl) and 2-(1-vinyl-1H-imidazol-3-ium-3-yl) acetate (CCIm), were introduced into the CAB-PILs skeleton. In this case, we proved the excellent characteristics of the catalyst containing both Lewis base and Bronsted acid sites for converting CO2 to cyclic carbonate under mild conditions. The catalyst showed good reusability and remained excellent activity after five reaction cycles. Combined with XPS, FTIR and DFT calculations, it is proved that the CCIm ionic monomer not only play the role of CO2 absorption center, but also has synergistic effect with CEImCl in CAB-PILs to promote cycloaddition reaction.

Synthesis of methacrylate polyanion chains via RAFT polymerization, kinetic study. Thermal properties of its copolymers with MMA and monomers’ reactivity ratios

Polyanionic chains, in which multiple monomeric units bear anion groups as counter ions to Li+, are excellent candidates for the preparation of polymer-based electrolytes, where anion movement is restricted, while lithium ions are free to move in the polymer matrix The aforementioned, are characterized as single Li-ion polymer electrolytes, and a great research effort is currently focused on the controlled synthesis and molecular characterization of such materials. Herein, we report the synthesis of Potassium 3-sulfonyl (trifluoromethane sulfonyl) imide propyl methacrylate (MASTFSIK) ionic monomer and its controlled polymerization kinetics, using RAFT techniques, while the progression of polymer tacticity is also noted in relation to the molecular weight of the growing polyanionic chains. The ion – exchange reaction with LiClO4 can be used to obtain the lithiated analog (PMASTFSILi). A series of linear copolymers (PMMA-co-PMASTFSILi) was synthesized with comparable degree of polymerization and varying compositions, considering the different monomeric units, for their thermal properties to be evaluated. The data suggest the presence of strong ionic interactions within the polymer matrix, resulting in a significant increase of the glass transition temperature for the polyanionic samples. The reactivity ratios of the MMA, MASTFSIK monomers were studied with various methods (FR, inv FR, KT, COPOINT), showing a preferential propagation of the MASTFIK monomer at low monomer consumption.

Solid polymer electrolytes of ionic liquids via a bicontinuous ion transport channel for lithium metal batteries

Polymer electrolytes with bicontinuous nanostructures for lithium metal batteries were prepared by UV-polymerization of hydrophobic domains in microemulsions of ionic liquids, amphiphilic ionic liquids, lithium salts and monomers.

High-Surface-Area Metalloporphyrin-Based Porous Ionic Polymers by the Direct Condensation Strategy for Enhanced CO2 Capture and Catalytic Conversion into Cyclic Carbonates.

Metalloporphyrin-based porous organic polymers (POPs) that behave as advanced biomimetic nanoreactors have drawn continuous attention for heterogeneous CO2 catalysis in the past decades. Inspired by the double activation model of epoxides, the design and synthesis of metalloporphyrin-based porous ionic polymers (PIPs) are considered as one of the most promising approaches for converting CO2 to cyclic carbonates under cocatalyst- and solvent-free conditions. To overcome the obstacle of poor reaction activity of ionic monomers or highly irregular stacking architecture, in this paper, we have proposed and demonstrated a modular bottom-up approach for constructing a series of high-surface-area metalloporphyrin-based PIPs in high yields by the direct condensation strategy, thus boosting the close contact of multiple active sites and achieving the enhanced CO2 capture and catalytic conversion into cyclic carbonates with high turnover frequencies under mild conditions. These recyclable aluminum-porphyrin-based PIPs are featured with high surface areas, prominent CO2 adsorptive capacities, rigid porphyrin skeletons, and flexible ionic pendants, as well as the matched amounts and spatial positions of metal centers and ionic sites, in which is demonstrated to be one of the quite competitive catalysts. Therefore, this strategy of introducing ionic components into the porphyrin frameworks as flexible side chains rather than main chains and adjusting the reactivity ratios of comonomers by structure-oriented methods, provides feasible guidance for the multifunctionalization of metalloporphyrin-based POPs, thereby increasing the accessibility of multiple active sites and improving their synergistic catalytic behavior.

Towards improved performance of waterborne polymer dispersions through creation of dense ionic interparticle network within their films

To overcome the main challenge of low performance of the waterborne polymer coatings due to the particulate nature of the polymer dispersions and the complex film formation process, in this work we implemented the strategy of ionic complexation between oppositely charged waterborne polymer particles. For that aim, doubled charged ionic monomers ithaconic acid (IA) and styrenic 1,4-diazabicyclo[2.2.2]octane (DABCO) were used to densely functionalize (meth)acrylic film forming polymer particles, synthesized by seeded semi-batch emulsion polymerization to produce high solids content anionically and cationically charged polymer dispersions, respectively. The main advantage of the double charges in the selected ionic monomers is that they provide high ionic charge density onto charged particles at lower content of ionic monomers.The blending of these oppositely, densely charged and concentrated dispersions resulted in instantaneous coagulation. To postpone the immediate complexation, water-soluble non-ionic polymeric stabilizing species as steric obstacles around the colloids were employed, which allowed to prepare colloidally stable blends and to prepare ionic complexed films. Certainly, the established ionic complexes between carboxylic acids of IA anionic monomer and quaternary ammonium groups of DABCO units within the films improved substantially the mechanical properties and the water sensitivity of the ionic complexed polymeric films with respect to individual films and the reference blend, in which ionic bonding was prevented by pH control. Moreover, the dense ionic network formed within the film actuated as a strong barrier to the leakage of all the water-soluble species during film immersion in water. Beside simple strategy towards improved performance of waterborne coatings, these results offer further extension of their application potential.

Energy Transfer in Aqueous Light Harvesting Antennae Based on Brush-like Inter-Conjugated Polyelectrolyte Complexes.

Conjugated polyelectrolytes (CPEs) have the potential to serve as building blocks of artificial light-harvesting systems. This is primarily due to their delocalized electronic states and potential for hierarchical self-assembly. We showed previously that inter-CPE complexes composed of oppositely charged exciton-donor and exciton-acceptor CPEs displayed efficient electronic energy transfer. However, near ionic charge equivalence, complexed CPE chains become net-neutral and thus experience a precipitous drop in aqueous solubility. To increase the stability and to rationally manipulate the phase behavior of inter-CPE complexes, we synthesized a series of highly water-soluble exciton-donor CPEs composed of alternating ionic and polar nonionic fluorene monomers. The nonionic monomer contained oligo(ethyleneglycol) sidechains of variable length. We then formed exciton donor-acceptor complexes and investigated their relative energy transfer efficiencies in the presence of a fixed exciton-acceptor CPE. We find that, even when the polar nonionic sidechains become quite long (nine ethyleneglycol units), the energy transfer efficiency is hardly affected so long as the inter-CPE network retains a net polyelectrolyte charge. However, near the onset of spontaneous phase separation, we observe a clear influence of the length of the oligo(ethyleneglycol) sidechains on the photophysics of the complex. Our results have implications for the use of polyelectrolyte phase separation to produce aqueous light-harvesting soft materials.

Rational Design of Solid Polymer Electrolyte Based on Ionic Liquid Monomer for Supercapacitor Applications via Molecular Dynamics Study.

The safety concern arising from flammable liquid electrolytes used in batteries and supercapacitors drives technological advances in solid polymer electrolytes (SPEs) in which flammable organic solvents are absent. However, there is always a trade-off between the ionic conductivity and mechanical properties of SPEs due to the lack of interaction between the ionic liquid and polymer resin. The inadequate understanding of SPEs also limits their future exploitation and applications. Herein, we provide a complete approach to develop a new SPE, consisting of a cation (monomer), anion and hardener from ions-monomers using molecular dynamics (MD) simulations. The results show that the strong solid-liquid interactions between the SPE and graphene electrode lead to a very small gap of ∼5.5 Å between the components of SPE and electrode, resulting in a structured solid-to-liquid interface, which can potentially improve energy storage performance. The results also indicated the critical role of the mobility of free-standing anions in the SPE network to achieve high ionic conductivity for applications requiring fast charge/discharge. In addition, the formations of hardener-depleted regions and cation-anion-poor/rich regions near the uncharged/charged electrode surfaces were observed at the molecular level, providing insights for rationally designing the SPEs to overcome the boundaries for further breakthroughs in energy storage technology.

Synthesis and evaluation of novel aromatic acrylic monomers for optically clear adhesive with high refractive index

AbstractConventional optical polymers have low refractive index; (RI &lt;1.5) which limit their usage in the field of optoelectronics. Therefore, two types of aromatic monomers with highRIvalue were developed; that is, ionic monomer (PA.HEMA.NEt3.H+) withRI = 1.5150 and monomer (PA.BA.GMA) withRI = 1.5403. The monomers were then individually combined with a newly synthesized oligomer based on phthalic anhydride epoxy acrylate; that is, (EA.PA) withRI = 1.5567. The structures of the synthesized monomers and oligomer were confirmed by NMR and FTIR spectroscopy and the chemical titration of the structure end groups. Different combinations of the monomers with oligomer EA.PA were examined to develop a UV‐curing adhesive with appropriate viscosity. According to TGA and DMTA test results, the composition containing oligomer EA.PA showed improved thermal degradation stability and high glass transition temperature. The lap shear adhesion test showed positive effect of oligomer EA.PA and PA.BA.GMA with an adhesion strength of up to 1.2 MPa. TheRIvalue of the composition containing PA.BA.GMA and oligomer EA.PA was measured as 1.55 which is qualified for the most applications in optoelectronic. The improvement inRIvalue may be well attributed to the presence of aromatic rings in the polymer chain backbone. The high degree of aromaticity is in favor with the improved thermal stability in adhesive composition.

Glass transition of random heteropolymers: A molecular dynamics simulation study in melt, in water, and in vacuum

Random heteropolymers (RHPs) have a long history of being studied as toy models for protein folding. Previous computational studies applied statistical mechanics or coarse-grained methods to investigate the RHP phase transition; here, we use atomistic molecular dynamics (MD) simulations to explore the factors affecting the glass transition temperature (Tg) and the mobility of a complex class of RHPs. Our RHPs consist of four methyl methacrylate-based monomers with side chains mimicking different classes of amino acids. We explore the dynamical features in the RHP melts with random sequence mixtures and show that instead of a sharp pseudo-second-order glass transition, as for PMMA, RHPs with low ionic contents show a soft and gradual transition and those with increased content of ionic monomers show a sharp transition. Meanwhile, the configurational entropy of the backbone dihedral angle decreases suddenly in both PMMA and RHPs as a common signature of the glass transition. The dynamical spatial heterogeneity during the glass transition is related to both the chemical structure of the monomers and their positions along the chain. Moreover, chain mobility depends on the content of ionic monomers and types of counterions. The comparison with the single-chain nanoparticles (SCNPs) in water and in vacuum shows “breathing dynamics” with higher mobility. Our work characterizes the physicochemical properties of the RHP melts as a group of emerging bio-inspired polymer materials.