Tailoring refractive index dispersion in ionic liquids: The influence of charge delocalization in cations.

In this work, we study the contributions that different molecular blocks have in the wavelength-dependence of the refractive index in ionic liquids. The ionic liquids chosen for this work are combinations of the bis(trifluoromethylsulfonyl)imide anion with cations based on four different heterocycles with different extents of charge delocalization. The analysis is performed in terms of the experimental electronic polarizability, which is obtained by combining measurements of refractive index curves and densities via the Lorentz-Lorenz equation. Exploiting the additivity of electronic polarizability in ionic liquids, the contribution of the anion and the heterocycles of the cations is separated from that of the alkyl chains. Our results show important differences in these contributions, revealing a key influence of the charge delocalization in the cationic rings on the behavior of the refractive index dispersion. The understanding of how different parts of ionic liquids affect their refractive index dependence on wavelength would allow to gain precise control of this magnitude, enabling the development of customized optical materials for diverse applications in photonics and sensing technologies.

Application of new tetra-cationic imidazolium ionic liquids for capture and conversion of CO2 to amphiphilic calcium carbonate nanoparticles as a green additive in water based drilling fluids.

Conversion and capture of carbon pollutants based on carbon dioxide to valuable green oil-field chemicals are target all over the world for controlling the global warming. The present article used new room temperature amphiphilic imidazolium ionic liquids with superior surface activity in the aqueous solutions to convert carbon dioxide gas to superior amphiphilic calcium carbonate nanoparticles. In this respect, tetra-cationic ionic liquids 2-(4-dodecyldimethylamino) phenyl)-1,3-bis (3-dodecyldimethylammnonio) propyl) bromide-1-H-imidazol-3-ium acetate and 2-(4-hexyldimethylamino) phenyl)-1,3-bis(3-hexcyldimethylammnonio) propyl) bromide-1 H-imidazol-3-ium acetate were prepared. Their chemical structures, thermal as well as their carbon dioxide absorption/ desorption characteristics were evaluated. They were used as solvent and capping agent to synthesize calcium carbonate nanoparticles with controlled crystalline lattice, sizes, thermal properties and spherical surface morphologies. The prepared calcium carbonate nanoparticles were used as additives for the commercial water based drilling mud to improve their filter lose and rheology. The data confirm that the lower concentrations of 2-(4-dodecyldimethylamino) phenyl)-1,3-bis (3-dodecyldimethylammnonio) propyl) bromide-1-H-imidazol-3-ium acetate achieved lower seawater filter lose and improved viscosities.

Facile construction of heterogeneous dual-ionic poly(ionic liquid)s for efficient and mild conversion of CO2 into cyclic carbonates.

In the context of peaking carbon dioxide emissions and carbon neutrality, development of feasible methods for converting CO2 into high value-added chemicals stands out as a hot subject. In this study, P[D+COO-][Br-][DBUH+], a series of novel heterogeneous dual-ionic poly(ionic liquid)s (PILs) were synthesized readily from 2-(dimethylamino) ethyl methacrylate (DMAEMA), bromo-substituted aliphatic acids, organic bases and divinylbenzene (DVB). The structures, compositions and morphologies were characterized or determined by nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA), infrared spectroscopy (IR), scanning electron microscopes (SEM), and Brunauer-Emmett-Teller analysis (BET), etc. Application of the P[D+COO-][Br-][DBUH+] series as catalysts in converting CO2 into cyclic carbonates showed that P[D+COO-][Br-][DBUH+]-2/1/0.6 was able to catalyze epiclorohydrin-CO2 cycloaddition the most efficiently. This afforded chloropropylene carbonate (CPC) in 98.4% yield with ≥ 99% selectivity in 24 hr under solvent- and additive-free conditions at atmospheric pressure. Reusability experiments showed that recycling of the catalyst 6 times only resulted in a slight decline in the catalytic performance. In addition, it could be used for the synthesis of a variety of differently substituted cyclic carbonates in good to excellent yields. Finally, key catalytic active sites were probed, and a reasonable mechanism was proposed accordingly. In summary, this work poses an efficient strategy for heterogenization of dual-ionic PILs and provides a mild and environmentally benign approach to the fixation and utilization of carbon dioxide.

Enhanced CO2 conversion through confinement of cross-linked ionic polymer within the pores of porous carbon materials.

It is crucial to employ an integrated catalyst to avoid the complications of the recovery process. This work reports the fabrication of porous carbon@ionic liquid (PC@IL) composites with readily accessible active ion sites, achieved by confining cross-linked ionic liquid (IL) within the channels of porous carbon (PC). The incorporation of porous carbon not only confines the IL within its framework, creating microsites for CO2 adsorption and conversion, but also simplifies catalyst recovery. The results indicate that PC@IL composites exhibit excellent cycloaddition activity towards CO2 in a co-catalyst- and solvent-free environment. Notably, PC@IL(C)-24 demonstrates remarkable catalytic performance across various epoxides under 1 bar of CO2, with yields above 90 % at 90 °C for 12 h, and achieving a remarkable styrene carbonate yield of up to 92.8 % under a CO2 pressure of 1 bar (at 100 °C for 12 h). Control experiments confirm that the confinement effect exerted by N,S co-doped carbon on cross-linked IL plays a pivotal role in enhancing both stability and activity of PC@IL composites, thereby providing novel insights for designing functionalized porous carbon catalysts for CO2 cycloaddition conversion.

Advancements in ionic liquid-based corrosion inhibitors for sustainable protection strategies: from experimental to computational insights.

The global corrosion cost is estimated to be around 2.5 trillion USD, which is more than 3 % of the global GDP. Against this background, large efforts have been made to find effective corrosion inhibitors. Ionic liquids (ILs) are nowadays regarded as reliable functional materials and one of the most promising classes of anticorrosion agents. Not only are they efficient in preventing corrosion of iron and other metals, but they are also relatively inexpensive, need no solvents, and are non-toxic to humans This review addresses both experimental and theoretical investigations conducted to IL-based corrosion inhibitors (CIs). It covers various ILs used, synthesis methods, and their performance in diverse corrosive environments. Electrochemical techniques like EIS and potentiodynamic polarization, along with computational approaches including quantum chemical calculations and DFT, provide valuable insights into corrosion inhibition mechanisms and the interactions between anticorrosion agents-surfaces. The synergistic combination of experimental and theoretical approaches enhances our understanding of corrosion inhibition, enabling the design and optimization of effective and sustainable corrosion protection strategies. This review consolidates the existing knowledge on ionic liquid-based corrosion inhibitors, highlights the key findings from both experimental and theoretical investigations, and points out possible directions for further studies in this area.

Preparation of an imidazolium-based poly(ionic liquid) functionalized magnetic three-dimensional graphene oxide for magnetic solid phase extraction of pyrethroids from tea samples.

In this work, an imidazolium-based poly(ionic liquid) (poly(1-dodecyl-3-vinyl-imidazolium bromide) functionalized magnetic three-dimensional graphene oxide (Fe3O4@3D-GO@poly(ImC12+Br-)) was synthesized via a vacuum freezing-drying method and used as a magnetic solid phase extraction (MSPE) adsorbent for the efficient extraction of pyrethroid pesticides from tea samples. The prepared Fe3O4@3D-GO@poly(ImC12+Br-) was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), vibrating sample magnetometer (VSM) and X-ray photoelectron spectrogram (XPS). Due to its large specific surface area and the ability to offer multiple intermolecular interactions, including π-π stacking, hydrophobic and hydrogen bond interactions, the prepared Fe3O4@3D-GO@poly(ImC12+Br-) showed high extraction efficiency for pyrethroids. The experimental parameters were optimized by a combination of single-factor method and Box-Behnken design to improve the extraction efficiency. Under the optimum conditions, coupled with high performance liquid chromatography (HPLC), a sensitive analytical method was developed for the determination of pyrethroids, and the proposed method showed wide linear ranges (1.00-100 µg L-1) with correlation coefficients (R) ranging from 0.9980 to 0.9994, low limits of detection (0.100 µg L-1) and good repeatability with intra-day relative standard deviations (RSDs) in the range of 2.90-5.53 % and inter-day RSDs in the range of 1.83-7.76 %. Moreover, the developed method was successfully applied to the determination of pyrethroids in tea samples and satisfactory recoveries ranging from 82.37 % to 114.34 % were obtained. The results showed that the developed Fe3O4@3D-GO@poly(ImC12+Br-) was an ideal, effective and selective material for the extraction and enrichment of pyrethroids from tea samples.

Polymeric ionic liquids containing copper(I) and copper(II) ions as gas chromatographic stationary phases for olefin separations.

Copper(I) ions (Cu+) are used in olefin separations due to their olefin complexing ability and low cost, but their instability in the presence of water and gases limits their widespread use. Ionic liquids (ILs) have emerged as stabilizers of Cu+ ions and prevent their degradation, providing high olefin separation efficiency. There is limited understanding into the role that polymeric ionic liquids (PILs), which possess similar structural characteristics to ILs, have on Cu+ ion-olefin interactions. Moreover, copper ions with diverse oxidation states, including Cu+ and Cu2+ ions, have been rarely employed for olefin separations. In this study, gas chromatography (GC) is used to investigate the interaction strength of olefins to stationary phases composed of the 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C6MIM+][NTf2-]) IL and the poly(1-hexyl-3-vinylimidazolium [NTf2-]) (poly([C6VIM+][NTf2-])) PIL containing monovalent and divalent copper salts (i.e., [Cu+][NTf2-] and [Cu2+]2[NTf2-]). The chromatographic retention of alkenes, alkynes, dienes, and aromatic compounds was examined. Incorporation of the [Cu2+]2[NTf2-] salt into a stationary phase comprised of poly(dimethylsiloxane) resulted in strong retention of olefins, while its addition to the [C6MIM+][NTf2-] IL and poly([C6VIM+][NTf2-]) PIL allowed for the interaction strength to be modulated. Olefins exhibited greater affinities toward IL and PIL stationary phases containing the [Cu2+]2[NTf2-] salt compared to those with the [Cu+][NTf2-] salt. Elimination of water from both copper salts was observed to be an important factor in promoting olefin interactions, as evidenced by increased olefin retention upon exposure of the stationary phases to high temperatures. To evaluate the long-term thermal stability of the stationary phase, chromatographic retention of probes was measured on the [Cu2+]2[NTf2-]/[C6MIM+][NTf2-] IL stationary phase after its exposure to helium at a temperature of 110 °C.

The Application of Green Solvents in the Synthesis of S-Heterocyclic Compounds-A Review.

Cyclic organic compounds containing sulfur atoms constitute a large group, and they play an important role in the chemistry of heterocyclic compounds. They are valuable intermediates for the synthesis of other compounds or biologically active compounds themselves. The synthesis of heterocyclic compounds poses a major challenge for organic chemists, especially in the context of applying the principles of "green chemistry". This work is a review of the methods of synthesis of various S-heterocyclic compounds using green solvents such as water, ionic liquids, deep eutectic solvents, glycerol, ethylene glycol, polyethylene glycol, and sabinene. The syntheses of five-, six-, and seven-membered heterocyclic compounds containing a sulfur atom or atoms, as well as those with other heteroatoms and fused-ring systems, are described. It is shown that using green solvents determines the attractiveness of conditions for many reactions; for others, such use constitutes a real compromise between efficiency and mild reaction conditions.

Investigation of laccase activity in cholinium-based ionic liquids using experimental and molecular dynamics techniques.

Laccases hold great potential for biotechnological applications, particularly in environmental pollutant remediation. Laccase activity is governed by the solvent environment, and ionic liquids (ILs) emerge as a versatile solvent for activation or stabilization of enzymes. Herein, effects of cholinium-based ILs formulated with carboxylic acids, inorganic acid, and amino acids as anionic species, on the catalytic activity of laccase from Trametes versicolor were investigated by experimental and computational approaches. Experimental results showed that laccase activity was enhanced by 21.39 % in 0.5 M cholinium dihydrogen citrate ([Cho][DHC]), in relation to the laccase activity in phosphate buffer medium. However, cholinium aminoate ILs negatively affected laccase activity, as evidenced by the partial deactivation of laccase in both cholinium glycinate and cholinium phenylalaninate, at concentrations of 0.1 M and 0.5 M, respectively. Molecular dynamics studies revealed that the enhancement of laccase activity in [Cho][DHC] might be attributed to the highly stabilized and compact structure of laccase, facilitating a better internal electron transfer during the laccase-substrate interactions. Enhanced catalytic performance of laccase in [Cho][DHC] was postulated to be driven by the high accumulation level of dihydrogen citrate anions around laccase's surface. [Cho][DHC] holds great promise as a cosolvent in laccase-catalyzed biochemical reactions.

Diffusion-Regulated Interfacial Polymerization of Hierarchically Microporous Polyamide Membranes for Permselective Gas Separations.

Interfacial polymerization has emerged as a robust method for fabricating task-specific polyamide (PA) membranes. However, the limited microporosity of highly cross-linked PA membranes constrains their effectiveness in gas separation applications. Herein, we introduce an ionic liquid (IL)-regulated interfacial polymerization process to fabricate polyamide nanofilms incorporating kinked tetrakis (4-aminophenyl) methane monomers. In situ ultraviolet-visible spectroscopy demonstrates that the diffusion of 1,3,5-benzenetricarbonyl trichloride (TMC) toward the interface increases with the IL/H2O ratio, leading to the formation of a more compact membrane with a higher cross-linking degree. The PA-TAM7/3-60 min membrane exhibits a CO2 permeance of 29.8 GPU and a CO2/CH4 selectivity of 109, exceeding the 2008 Robeson upper bond. Additionally, the highly cross-linked structure imparts the membranes with notable plasticization resistance. Mixed-gas tests (CO2/CH4 = 50/50, v/v) reveal that the PA-TAM7/3-60 min membrane experiences only a 2% reduction in CO2 permeance and a 10% decrease in CO2/CH4 selectivity at a CO2 partial pressure of 300 PSIG, compared to its performance at 30 PSIG. The ease of tuning membrane structure and gas separation performance, along with its excellent plasticization resistance, underscores the potential of these PA membranes for task-specific gas separations.

Electro-Co-Polymerisation of Polypyrrole-Polyaniline Composites in Ionic Liquids for Metal-Free Hydrogen Evolution Electrodes.

Pure organic films consisting of polypyrrole, polyaniline and a composite of polypyrrole and polyaniline electrodeposited in the ionic liquid EMIM-TFSI onto mesoporous carbon electrodes are tested for their hydrogen evolution reaction capabilities. The use of these intrinsically conducting polymers is seen as a way of stepping away from expensive and rare metallic catalysts. Co-polymerisation of polypyrrole and polyaniline in a 1 : 10 ratio in EMIM-TFSI was found to be doped with the TFSI- anion and be much more active to the hydrogen evolution reaction when compared to pure polymers. Tafel analysis of the composite gave a value of 144 mV/dec indicating that the Volmer step is the rate limiting step. However, stability tests showed an improvement in the composite's overpoential performance for the hydrogen evolution reaction.

Solvent Dependence of Ionic Liquid-Based Pt Nanoparticle Synthesis: Machine Learning-Aided In-Line Monitoring in a Flow Reactor.

Colloidal platinum nanoparticles (Pt NPs) possess a myriad of technologically relevant applications. A potentially sustainable route to synthesize Pt NPs is via polyol reduction in ionic liquid (IL) solvents; however, the development of this synthetic method is limited by the fact that reaction kinetics have not been investigated. In-line analysis in a flow reactor is an appealing approach to obtain such kinetic data; unfortunately, the optical featurelessness of Pt NPs in the visible spectrum complicates the direct analysis of flow chemistry products via ultraviolet-visible (UV-vis) spectrophotometry. Here, we report a machine learning (ML)-based approach to analyze in-line UV-vis spectrophotometric data to determine Pt NP product concentrations. Using a benchtop flow reactor with ML-interpreted in-line analysis, we were able to investigate NP yield as a function of residence time for two IL solvents: 1-butyl-1-methylpyrrolidinium triflate (BMPYRR-OTf) and 1-butyl-2-methylpyridinium triflate (BMPY-OTf). While these solvents are structurally similar, the polyol reduction shows radically different yields of Pt NPs depending on which solvent is used. The approach presented here will help develop an understanding of how the subtle differences in the molecular structures of these solvents lead to distinct reaction behavior. The accuracy of the ML prediction was validated by particle size analysis and the error was found to be as low as 4%. This approach is generalizable and has the potential to provide information on various reaction outcomes stemming from solvent effects, for example, differential yields, orders of reaction, rate coefficients, NP sizes, etc.

Ionic Gel Electrolytes for Electrochromic Devices.

Ionic gels are emerging as a promising solution for improving the functionality of electrochromic devices. They are increasingly drawing attention in the fields of electrochemistry and functional materials due to their potential to address issues associated with traditional liquid electrolytes, such as volatility, toxicity, and leakage. In extreme scenarios and/or the design of flexible devices, ionic gel electrolytes offer unique and invaluable advantages. This perspective delves into the application of ionic gels in electrochromic devices, exploring various methods to enhance their performance. After briefly introducing developments in ionic gels for electrochromic devices, the trends and key points of future development are discussed in detail.

Elastomeric Sensor-Triboelectric Nanogenerator Coupled System for Multimodal Strain Sensing and Organic Vapor Detection.

Stretchable, flexible sensors are one of the most critical components of smart wearable electronics and Internet of Things (IoT), thereby attracting multipronged research interest in the last decades. Following miniaturization and multicomponent development of several sensors in one could further propel the demand for wireless, multimodal platforms. Greener substitutes to conventional sensors that can operate in a self-powered configuration are highly desirable in terms of all-in-one sensor utilities. However, fabrication of composite-based ultrastretchable, self-powered sensors with multifunctionality, robustness, and conformability is still only partially achieved and, therefore, demands further investigation. In this work, we report a triboelectric nanogenerator (TENG)-based multifunctional strain and organic vapor sensor using cross-linked ethylene propylene diene monomer (EPDM) elastomer and conducting carbon black as active fillers in the presence of an ionic liquid. The resulting piezoresistive sensor demonstrates ultrahigh gauge factor (GF > 220k) and wide range strain sensitivity and is, therefore, suitable for subtle-to-high frequency motion detection devices. Supported by excellent triboelectric outputs (force sensitivity 0.5 V/N in the range of 50-300 N, maximum output voltage VOC ∼ 178 V, short circuit current ISC ∼ 18 µA, maximum power density 0.11 mW/cm2), the hybrid sensors offer remarkable mechanical toughness and seamless voltage generation under contact-separation, even after several thousand cycles of operations. Furthermore, the sensor substrates exhibited reproducible organic vapor-sensing behavior, with high responsivity of 1.92 and 1 for ethanol and acetone, respectively, under flowing vapor conditions. This work lays a strong foundation for developing a truly multimodal, TENG-based, self-powered organic vapor and strain sensors.

Effervescence tablets based on magnetic ionic liquids as simple microdevices for the in situ dispersive liquid-liquid microextraction of urinary biomarkers.

BACKGROUND: Magnetic ionic liquids (MILs) have been explored in dispersive liquid-liquid microextraction (DLLME). Their usage allows to substitute centrifugation and/or filtration steps by a quick magnetic separation. Besides, effervescence-assisted DLLME is one of the most known options to improve the dispersion of the extractant in the sample, while allowing to avoid the consumption of external energy during dispersion. Despite these interesting features, only one study incorporates MILs containing the tetrachloroferrate anion in effervescence tablets. These MILs are highly viscous and liquid at room temperature, thus compromising the stability of the tablets when used as extraction microdevices in effervescence-assisted DLLME, and only allowing their use in the conventional MIL-DLLME mode. RESULTS: A new class of effervescence tablets containing a Ni(II)-based MIL, that is solid at room temperature, is here proposed. This type of tablets permits their use, for first time, in the in situ DLLME mode, occurring through the transformation of a water-soluble MIL into a water-insoluble MIL microdroplet. This way, the tablet formulation included: the MIL, the metathesis reagent lithium bis[(trifluoromethyl)sulfonyl]imide, NaH2PO4 and K2CO3 as effervescence precursors salts, and Na2SO4 as salting-out and desiccating agent. The method is combined with high-performance liquid-chromatography and both fluorescence and ultraviolet detection, for the determination of monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and benzophenones (BPs), as biomarkers in urine. The method simply involved the addition of the effervescence tablet to the sample, thus taken place simultaneously the effervescence process and the metathesis reaction, without requiring any external energy consumption. The method presented limits of detection down to 10 ng L-1 for OH-PAHs and to 0.60 µg L-1 for BPs, inter-day relative standard deviations lower than 17 %, and average relative recoveries of 94 % in urine. The determined OH-PAHs contents in urine were between 0.40 and 16 µg L-1, and between 17.8 and 334 µg L-1 for BPs. SIGNIFICANCE: We have developed the first MIL-based effervescence tablets that are completely solid, thus improving the stability and robustness of these microdevices with respect to previously reported tablets involving MILs, while permitting to perform into the in situ DLLME mode (thus gaining in extraction efficiency). This approach including the MIL-based effervescence tablets constitutes an alternative on-site platform for the analysis of urine, as satisfactory precision, accuracy, and sensitivity are achieved despite not involving any external energy input within the analytical sample preparation setup. This method also constitutes the first application of MIL-based effervescence tablets for bioanalysis.

Hydrophilicity Dependent Distribution of Water at Ionic Liquids/Metal Interface Monitored by Electrochemical SERS.

The understanding of the interfacial processes is critically important for extending the practical application of ionic liquids, particularly for the role of interfacial water. In the electrochemical system based on ionic liquid electrolytes, small amounts of water at the interface generate a significant change in the electrochemical behaviors of ionic liquids. Therefore, the investigation on the interfacial behavior of water is highly desired in ionic liquids with different anions, water content, and hydrophilicity. Herein, based on the probe strategy, in situ surface enhanced Raman spectroscopy (SERS) combined with electrochemical control (EC-SERS) was developed to investigate the influence of hydrophilicity/hydrophobicity of ionic liquids on the interfacial water. The water-sensitive transformation reaction of 4,4'-dimercaptoazobenzene (DMAB) to para-aminothiophenol (PATP) was employed as a probe reaction for investigating the behavior of interfacial water. The changes of relative SERS intensities of DMAB to PATP served as an indication of the quantity variation of interfacial water. The results show that the transformation reaction efficiencies were critically dependent on the additional water contents, potential, and hydrophilicity of ionic liquids. With a very low molar fraction of additional water (Xw = 0.01), transformation efficiency of DMAB (the amount of interfacial water) followed the sequence of [BMIm]BF4 < [BMIm]PF6 < [BMIm]Tf2N. It was in agreement with the hydrophobicity order of the ionic liquids. With the increase in additional water content, the potential for the full transformation was positively moved, and the efficiency increased significantly. The stronger hydrophobicity allowed more water molecules to migrate to the interface, which was attributed to the difference in interactions between water and the anions of ionic liquids. It demonstrated that the small amount of water tended to gather at the interface in hydrophobic ionic liquids. Compared to traditional cyclic voltammetry, the EC-SERS technique combined with probe reactions is more sensitive to interfacial water. It is anticipated to develop as a promising tool for the investigating water-related issues at interfaces and to provide guidance to screen ionic liquids for practical application.

Bioinspired Functional Composites for Enhanced Thermally Conductivity via Fractal-Growth CuNP Fillers.

Thermal conduction for electronic devices has attracted extensive attention in light of the development of 5G communication. Thermally conductive materials with high thermal conductivity and extensive mechanical flexibility are extremely desirable in practical applications. However, the construction of efficient interconnected conductive pathways and continuous conductive networks is inadequate for either processing or actual usage in existing technologies. In this work, spherical copper nanoparticles (S-CuNPs) and urchin-inspired fractal-growth CuNPs (U-CuNPs), thermally conductive metal fillers induced by ionic liquids, were fabricated successfully through the electrochemical deposition method. Compared to S-CuNPs, the U-CuNPs shows larger specific surface contact area, thus making it easier to build a continuous conductive pathway network in the corresponding U-CuNPs/liquid silicone rubber (LSR) thermally conductive composites. The optimal loading of CuNP fillers was determined by evaluating the rheological performance of the prepolymer and the mechanical properties and thermal conductivity performances of the composites. When the filler loading is 150 phr, the U-CuNPs/LSR produces optimal mechanical properties (e.g., tensile strength and modulus), thermal conductivity (above 1000% improvement compared to pure LSR), and heating/cooling efficiency. The enhanced thermal conductivity of U-CuNPs/LSR was also confirmed through the finite element analysis (FEA) overall temperature distribution, indicating that U-CuNPs with larger specific surface contact areas exhibit more advantages in forming a continuous network in composites than S-CuNPs, making U-CuNPs/LSR a promising and competitive alternative to traditional flexible thermally interface materials.

Cytotoxicity and cell membrane interactions of choline-based ionic liquids: Comparing amino acids, acetate, and geranate anions.

Ionic liquids (ILs) have found diverse applications in research and industry. Biocompatible ILs, a subset considered less toxic than traditional ILs, have expanded their applications into biomedical fields. However, there is limited understanding of the toxicity profiles, safe concentrations, and underlying factors driving their toxicity. In this study, we investigated the cytotoxicity of 13 choline-based ILs using four different cell lines: Human dermal fibroblasts (HDF), epidermoid carcinoma cells (A431), cervical cancer cells (HeLa), and gastric cancer cells (AGS). Additionally, we explored the haemolytic activity of these ILs. Our findings showed that the cytotoxic and haemolytic activities of ILs can be attributed to the hydrophobicity of the anions and the pH of the IL solutions. Furthermore, utilising quartz crystal microbalance with dissipation (QCM-D), we delved into the interaction of selected ILs, including choline acetate [Cho][Ac] and choline geranate [Cho][Ge], with model cell membranes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). The QCM-D data showed that ILs with higher toxicities exhibited more pronounced interactions with membranes. Increased variations in frequency and dissipation reflected substantial changes in membrane fluidity and mass following the addition of the more toxic ILs. Furthermore, total internal reflection fluorescence microscopy study revealed that [Cho][Ac] could cause lipid rearrangements and pore formation in the membrane, while [Cho][Ge] disrupted the bilayer packing. This study advances our understanding of the cellular toxicities associated with choline-based ILs and provides valuable insights into their mechanisms of action concerning IL-membrane interactions. These findings have significant implications for the safe and informed utilisation of biocompatible ILs in the realm of drug delivery and biotechnology.

Bioactive Ion-Confined Ultracapacitive Memristors with Neuromorphic Functions.

The field of bioinspired iontronics, bridging electronic devices and ionic systems, has multiple biological applications. Carbon-based ultracapacitive devices hold promise for controlling bioactive ions via electric double layers due to their high-surface-area and biocompatible porous carbon electrodes. However, the interplay between complex bioactive ions and porous carbons remains unclear due to the variety of structures of bioactive ions present in biological systems. Herein, we investigate the adsorption behavior of a series of bioactive ammonium-based cations with varying alkyl chain lengths in nanoporous carbons. We find that strong physisorption results from the synergistic hydrophobic interaction and electrostatic attraction between porous carbons (with a negative zeta potential) and bioactive cations. Bioactive cations with varying alkyl chain lengths can be irreversibly physically adsorbed and confined within nanoporous carbons resulting in anion enrichment and depletion during electric polarization. This situation, in turn, results in a characteristic memristive behavior in all-carbon capacitive ionic memristor devices. Our findings highlight the relationship between the resistance state of the memristor and ion adsorption mechanisms in all-carbon capacitive devices, which hold potential for future transmitter delivery, biointerfacing, and neuromorphic devices.

Fate of persistent and mobile chemicals in the water cycle: From municipal wastewater discharges to river bank filtrate.

Persistent and mobile (PM) chemicals are considered detrimental for drinking water resources as they may pass through all barriers protecting these resources against pollution. However, knowledge on the occurrence of PM chemicals in the water cycle, that make their way into drinking water resources, is still limited. The effluents of six municipal wastewater treatment plants (WWTPs, n = 38), surface water of two rivers (n = 32) and bank filtrate of one site (n = 15) were analyzed for 127 suspected PM chemicals. In the rivers, median concentrations of 92 detected analytes ranged from 0.3 ng/L to 2.6 µg/L (tetrafluoroborate, BF4). Lower than average dilution from WWTP effluent to surface water of 43 PM chemicals suggests significant discharge from other sources. Many of these compounds were industrial chemicals, including cyanoguanidine, trifluoromethanesulfonic acid and BF4. River bank filtration (RBF) reduced the total concentration of 40 quantified compounds by 60 % from 19.5 µg/L in surface water to 8.4 µg/L in bank filtrate, on average. Of these, 20 compounds showed good removal (> 80 %), 14 intermediate (80 - 20 %) and 6 no removal (≤ 20 %), among them carbamazepine, hexafluorophosphate, and 2-pyrrolidone. 13 substances occurred at concentrations ≥ 0.1 µg/L in bank filtrate; for six of them toxicological data were insufficient for a health-based risk assessment. The regulatory definition of P and M chemicals, if used together with existing data on environmental half-lives (P) and Koc (M), showed little power to discriminate between chemicals well removed in RBF and those that were hardly removed. This comprehensive field study shows that RBF is a useful but incomplete barrier to retain PM chemicals from surface water. Thus, PM chemicals are, indeed, a challenge for a sustainable water supply.