Structure Of Cation Research Articles

Toward Understanding the Composition–Structure Relationship of Hybrid Organic Lead Iodide Compounds: Impact from Secondary Structures of Organic Cations

Toward Understanding the Composition–Structure Relationship of Hybrid Organic Lead Iodide Compounds: Impact from Secondary Structures of Organic Cations

Pseudorotaxane Ligand‐Induced Formation of Copper(I) Iodide Cluster Based Assembly Materials: From Zero to Three Dimensional

Comprehensive SummaryIn this work, we have successfully obtained a series of novel copper(I)–iodide clusters (CuI NCs) based assembly materials by combining supramolecular pseudorotaxane ligands {[Mebpe+]PF6–@CB[6] (CB[6] = cucurbit[6]uril), L’·PF6} and linkers {BPHF@CB[6], [BPHF = C14H20N4(PF6)2], L·PF6}, including discrete cluster CuI 1 and extended cluster organic frameworks MORF 1 and MORF 2. CuI 1 can be described as a dumbbell‐shaped molecule with its body‐centered site and two vertexes respectively occupied by one [Cu5I6]– cluster and two CB[6] held together by two L’·PF6 ligands. The crystal structures of MORF 1 and MORF 2 are 1D anionic chain and four‐fold interpenetrated 3D cationic diamondoid structure, respectively, which all featured intriguing alternating CB[6] and CuI NCs. Furthermore, CuI 1 exhibits outstanding thermochromic and piezochromic luminescence. MORF 1 and MORF 2 also are detected pressure dependent luminescence properties with an enormous blue‐shift of the near‐infrared (NIR) emission band under high pressure compression. These exciting and smart materials possess great potential in the application field of novel temperature and pressure sensors.

A green co‐treatment to accelerate the hydrolysis of sludge during anaerobic fermentation using free nitrous acid and sodium citrate

AbstractBackgroundAnaerobic fermentation of waste activated sludge to produce short‐chain fatty acids (SCFAs) is one of the means of sludge resource utilization. However, the protective effect of the extracellular polymeric substances (EPS) structure contained in sludge flocs can lead to a slow hydrolysis process, which inhibits the production of SCFAs.ResultsIn this study, a new step‐by‐step pretreatment method for breaking sludge flocs was adopted. The cationic complexing agent sodium citrate (C6H5Na3O7) was used first to break the cationic bridging structure of EPS, and then the strong oxidizing property of free nitrous acid (HNO2) was used to break the cell structure. The results showed that the C6H5Na3O7 dose of 0.10 g g−1 total suspended solids (TSS) was able to disintegrate EPS, and the optimal dose and pretreatment time of HNO2 under these conditions were 2.504 mg L−1 and 24 h, respectively, when the highest soluble chemical oxygen demand (SCOD) content of 1700 ± 25 mg L−1 was reached. SCFA production in the group of 0.10 g g−1 TSS with 2.504 mg L−1 HNO2 co‐pretreatment reached 1827 ± 40 mg COD L−1 at 8 days of fermentation.ConclusionThe presence of C6H5Na3O7 accelerated the degradation rate of HNO2 during fermentation, and the pH fluctuation of the system was lower compared to the HNO2 pretreatment alone. Moreover, the synergistic pretreatment significantly changed the bacterial community structure within the system and Petrimonas (47.62%), belonging to the hydrogen and acetic acid‐producing bacteria, was enriched, which promoted organic matter degradation and SCFA production. These findings will contribute to optimization of the sludge treatment process. © 2023 Society of Chemical Industry (SCI).

Characterization and Fate of a Septanosyl Ferrier Cation in the Gas and Solution Phases.

Ferrier reactions follow a mechanistic pathway whereby Lewis acid activation of a cyclic enol ether facilitates departure of an allylic leaving group to form a glycosyl Ferrier cation. Attack on the Ferrier cation provides a new acetal linkage concurrent with the transposition of the alkene moiety. The idiosyncratic outcomes of Ferrier reactions of seven-membered ring carbohydrate-based oxepines prompted an investigation of its corresponding septanosyl Ferrier cation. Experiments that characterized the ion, including gas-phase cryogenic IR spectroscopy matched with density functional theory-calculated spectra of candidate cation structures, as well as product analysis from solution-phase Ferrier reactions, are reported here. Results from both approaches revealed an inclination of the seven-membered ring cation to contract to five-membered ring structures. Gas-phase IR spectra matched best to calculated spectra of structures in which five-membered dioxolenium formation opened the oxepine ring. In the solution phase, an attack on the ion by water led to an acyclic enal that cyclized to a C-methylene-aldehydo arabinofuranoside species. Attack by allyl trimethylsilane, on the other hand, was diastereoselective and yielded a C-allyl septanoside.

Molecular understanding of cation effects on double layers and their significance to CO-CO dimerization.

Cation effects have been shown in numerous experiments to play a significant role in electrocatalysis. To understand these effects at the molecular level, we systematically investigate the structures and capacitances of electric double layers with a variety of cations as counter charges at Pt(111)-COad/water interfaces with ab initio molecular dynamics. It is encouraging to find that the computed Helmholtz capacitances for different cations are in quantitative agreement with experiments, and that the trend of cation effects on capacitances shows clear correlation with the structures of interface cations of differing sizes and hydration energies. More importantly, we demonstrate the Helmholtz capacitance as the key descriptor for measuring the activity of CO-CO dimerization, the rate-determining step for C2+ formation in electroreduction of CO and CO2. Our work provides atomistic insights into cation effects on electric double layers and electrocatalysis that are crucial for optimizing electrode and electrolyte materials.

Size-Dependent Geometrical Structures of Platinum Oxide Cluster Cations Studied by Ion Mobility–Mass Spectrometry

Structures of platinum oxide cluster cations (PtnOm+) were studied by ion mobility-mass spectrometry in combination with theoretical calculations. Structures of oxygen-equivalent PtnOn+ (n = 3-7) clusters were discussed from the comparison between their collision cross sections (CCSs) obtained by mobility measurement and simulated CCSs of their structural candidates from structural optimization calculations. Assigned structures of PtnOn+ were found to be composed of Pt frameworks and bridging O atoms, which follows the previous theoretical prediction on the neutral clusters. The structures change from planar (n = 3 and 4) to three-dimensional (n = 5-7) with increasing cluster size by deforming platinum frameworks. Comparison with other group-10 metal oxide cluster cations (MnOn+; M = Ni and Pd) showed that the PtnOn+ structures have a similar tendency to PdnOn+ rather than NinOn+.

Structure Transformation and Morphologic Modulation of Supramolecular Frameworks for Nanoseparation and Enzyme Loading.

Supramolecular framework (SF) encourages the emergence of porous structures with molecular flexibility while the dimension and morphology controls are less involved even though critical factors are vital for various utilizations. Targeting this purpose, two isolated components are designed and their stepped combinations via ionic interaction, metal coordination, and hydrogen bond into framework assembly with two morphologic states are realized. The zinc coordination to an ionic complex of polyoxometalate with three cationic terpyridine ligands constructs 2D hexagonal SF structure. A further growth along perpendicular direction driven by hydrogen bonding between grafted mannose groups leads to 3D SF assemblies, providing a modulation superiority in one framework for multiple utilizations. The large area of multilayered SF sheet affords a filtration membrane for strict separation of nanoparticles/proteins under gently reduced pressures while the granular SF assembly demonstrates an efficient carrier to load and fix horse radish peroxidase with maintained activity for enzymatic catalysis.

Organic Cation Design of Manganese Halide Hybrids Glass toward Low‐Temperature Integrated Efficient, Scaling, and Reproducible X‐Ray Detector

AbstractZero‐dimensional (0D) structure‐based manganese metal halides (MHs) are believed to be the most promising candidates for the next‐generation X‐ray scintillators due to their intense radioluminescence and environmental friendliness. However, low‐temperature (<180 °C), large‐area integration with more efficient X‐ray detection remains a tremendous challenge. Herein, from the perspective of cation (ionic liquids) structure design, the basic physical parameters of 0D MHs are regulated. And the calculations and experimental results demonstrate larger‐size cations that induce lower melting temperatures, larger exciton‐binding energies, larger ion migration energy, and tunable hardness, which are most desirable for MHscintillators. As a result, the champion materialHTP2MnBr4is achieved as glassy transparency wafer by low‐temperature (165 °C) melt‐quenching. Its application to X‐ray imaging features high spatial resolution (17.28 lp mm−1), scalability (>30 × 30 cm2), and integration with strong coupling force. Furthermore, HTP2MnBr4 glass with reproducible properties demonstrates a high light yield (38 000 photon MeV−1), excellent irradiation stability, and low detection limit (0.13 µGy s−1). The authors believe this work will provide guidance for MHscintillators to further commercial applications.

Regulating the Alkyl Chain Length of Quaternary Ammonium Salt to Enhance the Inkjet Printing Performance on Cationic Cotton Fabric with Reactive Dye Ink.

Cationic modification of cotton fabric was an effective way to improve the inkjet printing performance with reactive dye ink. However, there were few research studies that focused on the effect of the cationic agent structure, especially the alkyl chain length of the quaternary ammonium salt (QAS) cationic modifier, on the K/S value, dye fixation, and diffusion of inkjet-printed cotton fabric. In our work, different alkyl chain lengths of QAS were synthesized, and the inkjet printing performance of cationic cotton fabrics treated with different QASs was investigated. Compared with untreated cotton fabric, the K/S value and dye fixation of cationic cotton fabric treated with different QASs improved by 10.7 to 69.3% and 16.9 to 27.7%, respectively. With the increase in alkyl chain length of QAS, the interaction force between anionic reactive dyes and cationic QAS gradually increased mainly due to the fact that more N-positive ions on the quaternary ammonium group were exposed under the action of steric hindrance of alkyl chain length through the XPS spectrum. The electrostatic attraction between cationic cotton and reactive dye contributed to the diffusion of reactive dye into the fiber interior and enhanced the reaction probability of nucleophilic substitution reaction between monochlorotriazine reactive dye and the hydroxyl group of cotton fabric. The antibacterial result of the inkjet-printed cotton fabric indicated that when the alkyl chain length of QAS was higher than 8, the cationic cotton fabric obtained good antibacterial property.

Electrochemistry and Mass Transport of Ytterbium(III) in Bis(trifluoromethylsulfonyl)imide-Based Room-Temperature Ionic Liquids: Effects of Temperature, Viscosity, and Electrode Materials

Cyclic staircase voltammetry, rotating disk electrode voltammetry, controlled potential coulometry, and electrochemical impedance spectroscopy were used to probe the electrochemistry and mass transport of Yb3+ in the six room temperature ionic liquids based on the bis(trifluoromethylsulfonyl)imide (Tf2N−) anion with, 1-(1-butyl)−3-methylimidazolium (BuMeIm+), 1-(1-butyl)−1-methylpyrrolidinium (BuMePyro+), 1-(1-butyl)pyridinium (BuPy+), 1-butyltrimethylammonium (BuMe3N+), 1-ethyl-3-methylimidazolium (EtMeIm+), and tri(1-butyl)methylammonium (Bu3MeN+) cations. These investigations were carried out at glassy carbon as well as polycrystalline gold, platinum, and tungsten electrodes. The heterogeneous electron transfer rate of the quasireversible Yb3+/2+ redox couple was found to depend strongly on the electrode materials with the fastest rate observed at gold and the slowest rate found at tungsten, but was independent of the physicochemical properties of the various ionic liquids, in particular, the absolute viscosity. However, the mass transport of Yb3+ was dependent on the viscosity, and the temperature dependence of the diffusion coefficients was well represented by a Vogel-Tammann-Fulcher type expression for glass-forming ionic liquids. Analysis of the diffusion coefficient data with the Stokes-Einstein equation indicated that the solvodynamic radius of the diffusing Yb3+ was constant and independent of the structure and properties of the ionic liquid cations. The solvodynamic radius of Yb3+ was estimated from the “stick model” for the Stokes-Einstein equation. Application of the Random Closest Packing (RCP) model for spheres in consideration of the solvodynamic radius of the diffusing Yb3+ and the ionic radii of Yb3+ and Tf2N−, indicated that the former must diffuse in association with ∼5–6 of the anions.

Resolving the polar interface of infinite-layer nickelate thin films.

Nickel-based superconductors provide a long-awaited experimental platform to explore possible cuprate-like superconductivity. Despite similar crystal structure and d electron filling, however, superconductivity in nickelates has thus far only been stabilized in thin-film geometry, raising questions about the polar interface between substrate and thin film. Here we conduct a detailed experimental and theoretical study of the prototypical interface between Nd1-xSrxNiO2 and SrTiO3. Atomic-resolution electron energy loss spectroscopy in the scanning transmission electron microscope reveals the formation of a single intermediate Nd(Ti,Ni)O3 layer. Density functional theory calculations with a Hubbard U term show how the observed structure alleviates the polar discontinuity. We explore the effects of oxygen occupancy, hole doping and cation structure to disentangle the contributions of each for reducing interface charge density. Resolving the non-trivial interface structure will be instructive for future synthesis of nickelate films on other substrates and in vertical heterostructures.

A Novel Family of Lysosomotropic Tetracyclic Compounds for Treating Leukemia.

Acute myeloid leukemia (AML) is a heterogeneous hematological cancer characterized by poor prognosis and frequent relapses. Aside from specific mutation-related changes, in AML, the overall function of lysosomes and mitochondria is drastically altered to fulfill the elevated biomass and bioenergetic demands. On the basis of previous results, in silico drug discovery screening was used to identify a new family of lysosome-/mitochondria-targeting compounds. These novel tetracyclic hits, with a cationic amphiphilic structure, specifically eradicate leukemic cells by inducing both mitochondrial damage and apoptosis, and simultaneous lysosomal membrane leakiness. Lysosomal leakiness does not only elicit canonical lysosome-dependent cell death, but also activates the terminal differentiation of AML cells through the Ca2+-TFEB-MYC signaling axis. In addition to being an effective monotherapy, its combination with the chemotherapeutic arsenic trioxide (ATO) used in other types of leukemia is highly synergistic in AML cells, widening the therapeutic window of the treatment. Moreover, the compounds are effective in a wide panel of cancer cell lines and possess adequate pharmacological properties rendering them promising drug candidates for the treatment of AML and other neoplasias.

Anion influence on electronic and optical properties of several iodobismuthates

Complex lead iodide hybrid perovskites show high photovoltaic efficiency, but their use in solar cells may be limited due to Pb toxicity and its great bioavailability because of its solubility in water. Iodobismuthates can emerge as a promising alternative for solar cells, having no toxicity and exhibiting high stability in relation to the oxidation in air. To know if the iodoplumbates can be substituted with less toxic iodobismuthates without reducing the photovoltaic efficiency, microscopic contributions to the absorption coefficients are analyzed for two compounds. The absorption coefficients were obtained from first principles. To identify and quantify the most important contributions to the optical gaps, the absorption coefficients are split as an exact many-species expansion. From the results, the electronic and optical gaps are different. Additionally, the optical gap and the optical properties are rather insensitive to the cationic structure.

Toward solvent selection for the extractive removal of pyridine from fuels using ionic liquids: A QSPR study

In the present study, the distribution of pyridine between the ionic liquid (IL)-rich phase and hydrocarbon-rich phase has been predicted using the quantitative structure–property relationship (QSPR) approach. After a comprehensive survey in the literature, a large dataset including 51 ternary systems (i.e., IL (1), pyridine (2), and hydrocarbon (3)) was collected. The present dataset covers 19 cations, 14 anions, and 10 hydrocarbons. Therefore, the structural effect of each cation, anion, and hydrocarbon has been taken into account on the prediction of pyridine distribution between the IL-rich phase and hydrocarbon-rich phase. Multiple linear regression (MLR) and multi-layer perceptron (MLP) have been employed to develop the predictive/descriptive linear and non-linear models, respectively. Results showed that the final linear model (R2 = 0.9165, %AARD = 23.2722) and non-linear model (R2 = 0.9892, %AARD = 9.1936) have an acceptable prediction capability. By interpreting the selected descriptors of the QSPR model, the effect of changes in the cation, anion, and hydrocarbon structures on the extraction of pyridine was also studied. It was found that the size, branches, and cyclic or acyclic structure of hydrocarbons were important parameters affecting the pyridine distribution. Also, the size, branches, and position of the electronegative atoms (especially oxygen atoms) in the structure of anions as well as the alkyl side chain length and C-N bonds in the structure of cations could also affect the pyridine distribution.

Saturated C22-tailed cationic surfactant in concentrated brine: Structural evolution of wormlike micelles and rheological properties

Saturated C22-tailed ultra-long-chain imparts cationic surfactant stable chemical structure and strong hydrophobic interaction that favors the generation of wormlike micelles in brine. Such viscoelastic wormlike micellar fluid is expected to exhibit excellent salt-resistance and temperature-resistance. In this work, the self-assembled microstructures and microscopic flow properties of docosyl(trimethyl)azanium chloride (DCTAC) NaCl solutions were systematically investigated by means of cryogenic transmission electron microscopy (cryo-TEM), rheo-small angle neutron scattering (rheo-SANS), steady-state and dynamic rheology. It is found that DCTAC forms long, linear or branched, flexible or stiff wormlike micelles depending on NaCl concentration. The increase in salt content simultaneously promotes the growth of worm length and the formation of branches. While the worm chain elongation plays a dominant role in mid-range of NaCl concentrations, the branching formation acts as a leading role in supper high NaCl concentrations, which results in rheological properties experiencing a significant increase followed by a certain decrease upon increasing NaCl content up to ∼ 20 wt%. Moreover, DCTAC shows much better thickening power than corresponding homologue surfactants bearing shorter hydrophobic tail in brine, and DCTAC solution also shows much better temperature-resistance than them. These findings are helpful to understand salt effect on cationic surfactant self-assemble behavior, and the relationship between microstructure and solution macroscopical properties.

Influence of Li+/Al3+ on the corrosion behavior of Li-Al layered double hydroxides (LDHs) film on LA51 magnesium alloys

A hierarchical superhydrophobic Al-Li layered double hydroxide (LDH) films with different Li + /Al 3+ molar ratios of 1:1, 1:2, 2:1, pH value of 11.5 and reaction temperature of 125 °C, have been fabricated on the surface of Mg-5Li-1Al (LA51) alloys by hydrothermal method following the characteristics of controllable cation structure and exchangeable anion between layers. The properties of the films were investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). XRD and SEM results indicate that the Al-Li LDH films are successfully prepared on LA51 alloys. The contact angle (CA) was measured to be about 100.7°, indicating that the surface wettability of the film converted from hydrophilic to hydrophobic by surface modification. The corrosion resistance of Al-Li LDH films was evaluated by Tafel polarization curve and electrochemical impedance spectroscopy (EIS). Surprisingly, Tafel polarization curve and EIS test reveal that the Al-Li LDH films prepared at the molar ratio of Li + /Al 3+ 1:2, pH 11.5 and temperature 125 °C have better corrosion resistance in 0.1 M NaCl neutral solution. In addition, the formation mechanism and corrosion mechanism of the films on the surface of LA51 alloy are also proposed. It provides innovative synthetic materials and novel design ideas for the preparation of high-efficiency anti-corrosion coatings on LA51 alloys, whose application can be extended in industrial fields.

Crystal Facet and Electronic Structure Modulation of Perovskite Oxides for Water Oxidation

In water-splitting catalysts, exposing high-activity crystal facets with optimal electronic structures can significantly enhance the oxygen evolution reaction (OER) kinetics. In this work, we demonstrate a facile strategy for simultaneously modulating the preferential crystal facet and electronic structure of perovskite oxides for their use as water-electrolysis catalysts using a template-mediated growth approach. Experimental and computational analyses revealed that the preferred crystal facet of La0.5Sr0.5CoO3 (LSC) grown on MoReS2 was effectively modulated to the (110) plane, and the free energy barrier of the rate-determining step was lowered by such crystal facet engineering. Furthermore, the interfacial charge transfer between LSC and MoReS2 enabled the optimal electronic structure of the B-site cation in LSC. Consequently, LSC grown on MoReS2 exhibited an OER activity of 210 mV at 10 mA cm–2, surpassing the performance of state-of-the-art perovskite oxide-based catalysts. Our findings provide new insights into the design of efficient perovskite oxide-based electrocatalysts for water electrolysis.

Investigation of Thermodynamic Properties of Dimethyl Phosphate-Based ILs for Use as Working Fluids in Absorption Refrigeration Technology.

In the current research, the binary solution containing ionic liquid (IL), 1-ethyl-1-methylmorpholinium dimethyl phosphate ([C1C2MOR][DMP]), 1-ethyl-1-methylpiperidinium dimethyl phosphate ([C1C2PIP][DMP]), or N,N,N-triethyl-N-methylammonium dimethyl phosphate ([N1,2,2,2][DMP]) with ethanol are investigated as new working fluids for absorption refrigeration technology. The IL was mixed with ethanol, which was considered as a refrigerant. Experimental (vapor + liquid) phase equilibria (VLE) of these binary systems were measured by an ebulliometric method within a temperature range from T = (328.15 to 348.15) K with an increment of 10 K and pressures up to 90 kPa. Experimental VLE data were correlated using non-random two-liquid (NRTL) within the maximum average relative deviation of 0.45%, which confirms the effectiveness of using such a model for calculations. Each of the proposed binary systems exhibit a negative deviation from Raoult's law, which is a very important characteristic for working pairs used in absorption heat pumps or absorption refrigerators. From a technological point of view, measurements of physicochemical properties play an important role. In this research, liquid density and dynamic viscosity were determined at temperatures from T = (293.15 to 338.15) K at ambient pressure over the whole concentration range. These properties were correlated using empirical equations. From experimental density data, the excess molar volumes were determined and correlated using the Redlich-Kister type equation. Ionic liquid: [C1C2MOR][DMP] and [C1C2PIP][DMP] were synthesized and characterized using NMR analysis. The thermophysical characterization of pure ILs, including glass transition temperature (Tg) and heat capacity at the glass transition temperature (ΔgCp), was determined using the differential scanning calorimetry technique (DSC) at atmospheric pressure. In this work, the combination of basic studies on the effect of the cation structure of an ionic liquid on the properties of their solutions with ethanol and the possibility of future application of the tested systems in a viable refrigeration system are presented.

Temperature and Pressure Dependence of the Transport Properties of the Ionic Liquid Triethyloctylphosphonium Bis(trifluoromethanesulfonyl)amide, [P222,8][Tf2N

Viscosities of triethyloctylphosphonium bis(trifluoromethanesulfonyl)amide, [P222,8][Tf2N], are reported as a function of temperature [(273 to 363) K] and pressure (maximum 302 MPa) with a falling-body viscometer together with electrical conductivities (κ) measured by impedance spectroscopy at (283 to 348) K, to 250 MPa maximum pressure. pVT data were determined with a vibrating tube densimeter from (298 to 353) K to 50 MPa. Ion self-diffusion coefficients (DSi) were measured by steady-gradient spin-echo NMR [(313 to 365) K], and densities [(273 to 363) K] were determined with a vibrating tube densimeter, both at atmospheric pressure. The results were correlated with Walden and Stokes–Einstein–Sutherland relations. Velocity cross-correlation coefficients (VCC), distinct diffusion coefficients (DDC) and Laity resistance coefficients (LRC) were calculated from DSi and κ at 0.1 MPa. The DDC and LRC for [P222,8][Tf2N] and the pentyl-substituted analogue, [P222,5][Tf2N], showed differences for cation–cation and cation–anion velocity anti correlations, presumably due to the different cation structures. The high-pressure viscosities were used to predict the pressure dependence of the glass-transition temperature for [P222,5][Tf2N] and [P222,8][Tf2N]. Density scaling was applied to the high-pressure viscosities and conductivities of [P222,8][Tf2N] for comparison with [P222,5][Tf2N]. The scaling parameters are consistent with the theoretical treatment of Knudsen et al. for ionic liquids.

Effect of anions and cations on the self-assembly of ionic liquid surfactants in aqueous solution

Ionic liquid surfactants have shown increasing promise for substituting the traditional amphiphiles due to their flexible tunability and superior physicochemical properties. However, the effect of cationic structure and anion type on the surface properties of ionic liquid surfactants remains unclear. Herein, four ionic liquid surfactants [C12mim][BF4], [PyC12][Br], [C12mim][Br] and [PyC12][BF4] with the same alkyl side chain length were designed and synthesized. Their surface properties, such as micelle-free energy (ΔGmθ), surface tension reduction efficiency (ПCMC), and adsorption efficiency (pC20), and the influence of the type and structure of the anion and cation on their micellar physicochemical properties in aqueous solution were discussed according to the data. The proposed approach demonstrates that the critical micelle concentration (CMC) is determined by combining electrostatic and hydrophobic effects. When the anion is BF4−, the ionic liquid has a lower CMC, and BF4− has a superior hydrophobic effect, which allows the ionic liquid to form micelles more easily. In addition, the ionic liquid of tetrafluoroborate has higher interfacial activity (larger pC20) at the same temperature and its aqueous solution has lower surface tension, making it a more desirable surfactant. All four types of ionic liquids have negative values of ΔGmθ, implying that micelle formation is a spontaneous process. The surface activity of imidazolium- and pyridinium-based ionic liquids was slightly different from the critical micelle concentration under the same anion and carbon chain length. Imidazole and pyridine have highly similar hydrophobic and electrostatic effects, and the cation may not be the most critical factor affecting the surface properties.