Complete Composition Range Research Articles

Densities, refractive indices, and viscosities of N,N-diethylethanol ammonium chloride–glycerol or –ethylene glycol deep eutectic solvents and their aqueous solutions

In this work, we report new experimental data on density, ρ, refractive index, nD, and viscosity, η, of two deep eutectic solvents, N,N-diethylethanol ammonium chloride–glycerol (DEACG) and N,N-diethylethanol ammonium chloride–ethylene glycol (DEACEG), and their aqueous solutions, over the complete composition range, at temperatures from (298.15 to 343.15)K. Densities and viscosities were measured using the vibrating tube and the falling ball techniques, respectively, while the refractive index at the sodium D line was measured using an automatic refractometer. We aimed to represent the measured properties as a function of temperature and composition, and correlated them using the Redlich–Kister-type equation, for density, a polynomial function, for refractive index, and the Vogel–Fulcher–Tammann (VFT) equation, for viscosity.

Physical Properties of Binary Liquid Systems: Ethanoic Acid/Propanoic Acid/Butanoic Acid with Cresols

Density, viscosity and surface tension of nine binary liquid systems: ethanoic acid, propanoic acid and butanoic acid with o-cresol, m-cresol and p-cresol have been determined at 298.15, 308.15 and 318.15 K over the complete compositional range. From the experimental results the excess values of molar volume (V E), viscosity (η E), Gibbs free energy for the activation of flow (ΔG E) and surface tension (σ E) were evaluated. The excess values were fitted to the Redlich–Kister type equation using a nonlinear regression technique. The Grunberg–Nissan parameter, d, was also calculated. From the sign and magnitude of the V E, η E, ΔG E, σ E, and d values, it is concluded that specific interactions are present in all of the nine binary mixtures under study. V E is negative for carboxylic acid–cresol mixtures at all temperatures and over the entire composition range. The values of η E, ΔG E and σ E are positive over the whole range of composition and increase with increasing temperature at a constant mole fraction of the carboxylic acid, confirming the existence of specific interactions in these binary mixtures. Further, the viscosity data of the binary systems were fitted to various theoretical/empirical models. The binary viscosity data is well represented by the Auslander model. Surface tension data were fitted to various theoretical/empirical models. The binary mixture surface tension data are well represented by the model given by Zihao and Jufu.

Multicomponent Adsorption of Alcohols onto Silicalite-1 from Aqueous Solution: Isotherms, Structural Analysis, and Assessment of Ideal Adsorbed Solution Theory

Configurational-bias Monte Carlo (CBMC) simulations in the isobaric-isothermal version of the Gibbs ensemble (GE) were carried out to probe the adsorption from aqueous solutions of methanol and/or ethanol onto silicalite-1. This methodology does require neither specification of the chemical potential nor any reference to activity models based on experimental data. The CBMC-GE methodology can be applied to the complete range of mixture compositions from pure water to pure alcohols and can also be used when multiple solute types are present at high concentration. The simulations demonstrate high selectivities for the alcohols (α(ethanol) > α(methanol)) almost over the entire composition range. The ideal adsorbed solution theory is found to substantially underpredict the amount of sorbed water and leads to very large errors for low alcohol solution concentrations. The simulations indicate that, at lower loadings, the adsorbed alcohol molecules can serve as seeds for water adsorption but, at higher loadings, alcohols displace water molecules from their preferred region.

Effect of nano-silica on the phase inversion behavior of immiscible PA6/ABS blends

The phase inversion behavior of immiscible polyamide 6/acrylonitrile-butadiene-styrene (PA6/ABS) blends and the effect of hydrophobic nano-silica particles were studied. The phase morphology was characterized by scanning electron microscopy and selective extraction. The feasibility of rheological measurements to detect the co-continuity and phase inversion composition in the melt state was evaluated. The evolution of the storage modulus of the blends at a constant low frequency with composition showed a great enhancement of the elasticity when PA6 was the dispersed phase, and the maximum of the storage modulus at the evaluated frequency was definitely related to the phase inversion in pure blends. It was found that the PA6 was more likely to form the continuous phase, and a complete co-continuous composition range did not exist. The nano-silica particles showed selective distribution in the blends and a network-like structure of the nano-silica particles in the ABS phase was formed when ABS was the matrix, which invalidated the rheological technique to detect the phase inversion composition. A non-isothermal rheological procedure was designed to verify the phase inversion composition obtained by selective extraction measurement. Several models were employed to predict the phase inversion composition. It was confirmed that the viscosity ratio was the most important factor influencing the phase inversion. The introduction of hydrophobic nano-silica particles led to a shift of the phase inversion composition to higher ABS content due to the enhanced viscosity ratio.

Densities and refractive indices of the deep eutectic solvents (choline chloride + ethylene glycol or glycerol) and their aqueous mixtures at the temperature ranging from 298.15 to 333.15 K

Deep eutectic solvents (DES) are new emerging alternatives to conventional ionic liquids that may find a number of interesting applications in industrial and chemical processes. In this study, the densities, ρ, and refractive indices, nD, of the DESs (choline chloride+ethylene glycol) and (choline chloride+glycerol) and their aqueous mixtures were investigated at atmospheric pressure over the temperature range 298.15–333.15K and across a complete composition range. The excess molar volumes, VE, and refractive index deviations, ΔnD, were also calculated from experimental results. The calculated excess molar volumes were negative at all temperatures over the entire range of composition considered, suggesting the presence of strong interactions between water and the DES in the mixtures. The refractive index deviations, on the other hand, were found positive in the entire concentration range. The calculated properties were fitted to a Redlich–Kister type equation to correlate them to the temperature and composition. The correlations used satisfactorily represent the densities and refractive indices of the pure DESs and their aqueous binary mixtures as functions of temperature and composition as indicated by the low overall average absolute deviations obtained in the calculations.

Molar heat capacities of choline chloride-based deep eutectic solvents and their binary mixtures with water

In this study, the molar heat capacities, C P , of three choline chloride-based deep eutectic solvents (DESs); Reline, Ethaline and Glyceline, and their binary mixtures with water were determined. Using a heat flow differential scanning calorimeter, the heat capacities were measured at standard pressure from (303.2 to 353.2) K and over the complete range of composition. Results showed that the molar heat capacity increased with increasing temperature and, for the binary systems, with increasing DES concentration. The temperature-dependence of the pure DESs were successfully represented by a second-order empirical correlation with an AAD% of 0.05. The excess molar heat capacities, C P E , of the binary mixtures also determined and found generally negative over the whole composition range while exhibiting negative temperature dependence. The C P E values were fitted to a Redlich–Kister type equation to correlate them to the temperature and DES mole fraction and the molar heat capacities of the binary mixtures were predicted. The applied models successfully correlated the experimental C P data as functions of both temperature and composition.

Preparation of 24 Ternary Thin Film Materials Libraries on a Single Substrate in One Experiment for Irreversible High-Throughput Studies

For different areas of combinatorial materials science, it is desirable to have multiple materials libraries: especially for irreversible high-throughput studies, like, for example, corrosion resistance testing in different media or annealing of complete materials libraries at different temperatures. Therefore a new combinatorial sputter-deposition process was developed which yields 24 materials libraries in one experiment on a single substrate. It is discussed with the example of 24 Ti-Ni-Ag materials libraries. They are divided based on the composition coverage and orientation of composition gradient into two sets of 12 nearly identical materials libraries. Each materials library covers at least 30-40% of the complete ternary composition range. An acid etch test in buffered-HF solution was performed, illustrating the feasibility of our approach for destructive materials characterization. The results revealed that within the composition range of Ni < 30 at.%, the films were severely etched. The composition range which shows reversible martensitic transformations was confirmed to be outside this region. The high output of the present method makes it attractive for combinatorial studies requiring multiple materials libraries.

Interactions within a [Ionic Liquid + Poly(ethylene glycol)] Mixture Revealed by Temperature-Dependent Synergistic Dynamic Viscosity and Probe-Reported Microviscosity

Mixtures of ionic liquid (IL) with poly(ethylene glycol) (PEG) may afford media with favorable properties. Dynamic viscosities of mixtures of a common and popular IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) with PEGs of average molecular weight (MW) 200 (PEG200), average MW 400 (PEG400), number-average MW M(n) 570-630 (PEG600), and number-average MW M(n) 950-1050 (PEG1000) over a complete composition range at 10° intervals in the temperature range of 10-90 °C are measured. The temperature dependence of the dynamic viscosity shows ([bmim][PF(6)] + PEG) mixtures to behave as Newtonian fluids and is found to follow Arrhenius-type behavior. In the IL-rich region, excess logarithmic viscosities for the ([bmim][PF(6)] + PEG200) mixture are found to be negative and independent of the temperature. Mixtures of ([bmim][PF(6)] + PEG600) and ([bmim][PF(6)] + PEG1000) show rare and unusual viscosity "synergism" or "hyperviscosity" in the sense that the mixture viscosity is observed to be significantly higher than the viscosity of both the neat components forming the mixture, giving rise to large positive excess logarithmic viscosities. These positive excess logarithmic viscosities decrease with increasing temperature. Formation of extensive H-bonding between the IL and PEG more than compensates for the losses in Coulombic attractive and van der Waals interactions within [bmim][PF(6)] and PEG600/PEG1000, respectively, giving rise to viscosity synergism. This compensation is not enough for ([bmim][PF(6)] + PEG200) and ([bmim][PF(6)] + PEG400) mixtures. The evidence for H-bonding in the mixtures is provided by FTIR absorbance data. The product of the monomer-to-excimer emission intensity ratio and the lifetime of the intramolecular excimer fluorescence of a microfluidity probe, 1,3-bis(1-pyrenyl)propane (BPP), is used as a reflection of the microviscosity of the mixture at different temperatures. The microviscosity shows synergistic effects in all four ([bmim][PF(6)] + PEG) mixtures. The contribution of H-bonding to the microviscosity reported by BPP is observed to be more then that as compared to contributions of Coulombic and van der Waals interactions. Synergism in the dynamic viscosity and microviscosity of ([bmim][PF(6)] + PEG) mixtures is a complex interplay of inter- and intramolecular H-bonding as well as Coulombic and van der Waals type interactions.

On the elusive isotopic composition of lunar Pb

Highly radiogenic Pb isotope compositions determined for volcanic glass beads from the Apollo 14 soil sample 14163 are similar to those commonly determined for mare basalts and are correlated with chemical variations observed in the beads. This indicates that Pb unsupported by in-situ U decay has a similar origin in both glass beads and mare basalt samples and is likely to reflect variations of 238U/ 204Pb ( μ) in the lunar mantle. An alternative explanation that this Pb is a result of late equilibration with the radiogenic Pb present in soil is less likely as it would imply that all other characteristics of glass beads such as their chemistry must also be a consequence of equilibration near the lunar surface. Regardless of the origin of unsupported Pb, observed variations of Pb isotope compositions in the glass beads and mare basalts appear to be a result of two component mixing between a primitive reservoir with a μ-value similar to the Earth’s mantle and KREEP with a μ-value in excess of several thousand. This range cannot be explained by the fractionation of major rock forming minerals from the crystallising Lunar Magma Ocean and instead requires substantial extraction of sulphide late in the crystallisation sequence. The proportion of sulphide required to produce the inferred range places limits on the starting μ of the Moon prior to differentiation, demanding a relatively high value of about 100–200. Low μ indicated by several basalt samples and previously analysed volcanic glass beads can be explained by the preservation of an early (but post Ferroan Anorthosite) sulphide rich reservoir in the lunar mantle, while a complete range of Pb isotope compositions observed in the glass beads and mare basalts can be interpreted as mixing between this sulphide rich reservoir and KREEP.

Mutual diffusion in binary mixtures of ionic liquids and molecular liquids by dynamic light scattering (DLS)

The present study shows that dynamic light scattering (DLS) is capable of measuring mutual diffusion coefficients for binary mixtures of ionic liquids (ILs) with different molecular liquids over the complete composition range. Evidence is given that the light scattering signals are related to true molecular binary diffusion. The method stands out due to its ability to work non-invasively in macroscopic thermodynamic equilibrium with reasonable accuracy and within convenient measurement periods. Compared with other techniques, mixtures with distinctly higher viscosities can be probed. For exemplary binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO(4)]) with acetone, acetonitrile, dichloromethane, ethanol, or water as well as of 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO(3)]) with acetone, water, or methanol, mutual diffusivity data were measured over a wide range of composition at a temperature of 293.15 K. In general, the mutual diffusivity increases with increasing mole fraction of the molecular liquid and similarities to aqueous solutions of classical inorganic salts can be found. The characteristic behavior of the mutual diffusion coefficients is influenced by the nature of the chosen molecular liquid. For IL water mixtures, low light scattering intensities were observed despite the large refractive index difference of the pure components. The reason for this behavior may be the existence of water clusters in the mixtures. Additional measurements for IL acetone mixtures at temperatures ranging from 278.15 K to 323.15 K showed that the temperature dependence of the mutual diffusivity can be represented by Arrhenius functions and is increasing for decreasing mole fractions of acetone.

Densities, Viscosities and Refractive Indices of n- Butanol + Allyl Chloride Mixture at 298K

The density ρ, viscosity η, refractive index n and dielectric constant es of binary mixture of Allyl Chloride (AC) with n-Butanol including those of the pure liquids, were measured over the complete composition range at 298K. The experimental data is used to calculate excess molar volumes (v E ), excess permittivity (es E ), excess viscosity (η E ), excess refractive index, molar refraction, excess molar polarization and Dunstan’s constant. The variations of these parameters with composition and the effect of bonding in the binary mixture are discussed from the point of view of intermolecular interactions in these mixtures. The positive value of excess molar volume (v E ) is attributed to the breaking of H-bonded associated species formed between unlike molecule at 298K.

Studies on the phase diagram of CaCl 2–CaBr 2 system

A study on pseudo-binary CaCl 2–CaBr 2 system was carried out using differential thermal analysis (DTA) technique covering the complete composition range of the constituents between room temperature and 1073 K. From the DTA results the contour of solidus and liquidus temperatures with composition are plotted and the phase diagram of CaCl 2–CaBr 2 system is constructed. The solidus and liquidus curves exhibit a minimum at 971 K and at a composition of 56.5 mol% CaBr 2. Below 971 K, the system exhibits complete solid solution. Long-term equilibration of samples of several compositions was carried out at 923 and 673 K and the phases were characterized by XRD. The XRD results supported solid solution formation in the CaCl 2–CaBr 2 system between 673 and 923 K.

First principles calculations of theσ andχ phases in the Mo–Re and W–Re systems

The total energies of all the ordered configurations of theσ andχ phases have been calculated by using first principles methodology in both Mo–Re andW–Re systems. These two complex structures possess 5 and 4 inequivalent sitesgenerating 32 and 16 different ordered configurations, respectively, for a binaryA–B system. The converged total energies of all the fully relaxed structures have been used tocompute the occupancy of the inequivalent sites as a function of compositionand temperature by using the Bragg–Williams approximation in the completecomposition range. It is shown that the configurational entropy stabilizes theσ andχ phases in the Mo–Re and W–Re systems. The results evidence the preference of Re forlower coordination number site occupancy and are in very good agreement with theexperimental measurements. Tentative ab initio phase diagrams have also been drawn.

Experimental Measurement and Modeling of Vapor−Liquid Equilibrium for the Ternary System Water + Ethanol + 1-Butyl-3-methylimidazolium Chloride

Vapor−liquid equilibrium (VLE) data were measured for the ternary system water (1) + ethanol (2) + 1-butyl-3-methylimidazolium chloride ([bmim]Cl) (3). Complete T, x, and y data were obtained in a relatively wide range of ionic liquid (IL) mass fractions up to 0.8 and in a relatively complete composition range for the volatile binary pair. The nonrandom two-liquid (NRTL) equation was used for correlation and was revealed to be adequate for the ternary system in the experimental composition range. The ternary VLE behavior was also modeled by the correlation of two data sets, in which the ethanol mole fraction on IL-free basis is respectively at 0.1 and 0.98. In this way, the six data sets were reproduced satisfactorily, with root-mean-square deviations of 0.40 K for temperature and 0.0070 for vapor-phase mole fractions. Owing to the regular distribution of the experimental data, a good agreement between the experiment and the calculation was graphically presented. The effect of the IL on the VLE behavior o...

Experimental Study of the Dynamic Viscosity Deviations in the Binary Systems: Hexane + Ethylbenzene, + o-Xylene, + m-Xylene, + p-Xylene at 298.15 K

In this study experimental measurements of the thermophysical properties of binary mixtures containing hexane + aromatic hydrocarbon are continued. Here experimental data of the dynamic viscosity, η, at 298.15 K and atmospheric pressure, over the complete composition range are presented. As noted, the second compound of all mixtures belong to the same aromatic family, with a benzene ring having one ethyl chain or two methyl chains placed at different sites of the benzene ring. So, the molar mass for all four second compounds is exactly the same. Thus, these measurements will provide information about the influence of the methyl chain positions on the viscosity when it is mixed with hexane. From the measured values of the dynamic viscosity, dynamic viscosity deviations of the binary mixtures are determined and the viscosity deviations are compared with other deviation results for similar mixtures, and among the different binary mixtures.

Polymer Molecular Weight-Dependent Unusual Fluorescence Probe Behavior within 1-Butyl-3-methylimidazolium Hexafluorophosphate + Poly(ethylene glycol)

Poly(ethylene glycols) (PEGs) and room-temperature ionic liquids (ILs) are both projected as possible alternatives to volatile organic compounds (VOCs). Their potential usage in chemical applications, however, is often hampered by their limited and, in some cases, undesired individual physicochemical properties. Properties of mixtures of PEG with a common IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) are assessed via responses of three fluorescence probes: pyrene (Py) and pyrene-1-carboxaldehyde (PyCHO) are the dipolarity sensing probes and 1,3-bis-(1-pyrenyl) propane (BPP) is the probe for microfluidity. All three probes demonstrate anomalous fluorescence behavior within the mixture of [bmim][PF6] with four different PEGs of average molecular weight (MW) 200, 400, 600, and 1500 g.mol(-1), respectively, across complete composition range. Cybotactic region dipolarity of the probe Py within the mixtures is observed to be higher than that expected from ideal additive behavior. PyCHO lowest energy fluorescence maxima implying the static dielectric constant around the cybotactic region shows values within the mixtures to be even higher than that in neat PEG, the component having higher static dielectric constant of the two, clearly indicating the milieu to have anomalously high dipolarity. "Hyperpolarity" inherent to the PEG+[bmim][PF6] mixture is confirmed. Intramolecular excimer-to-monomer fluorescence intensity ratio of BPP indicates the microfluidity within the mixture to be even lower than that within neat [bmim][PF6], the component with lowest microfluidity. Presence of strong solvent-solvent interactions within the mixture is proposed to be the major reason for the anomalous fluorescence probe responses. Specifically, extensive hydrogen-bonded network involving termini hydroxyls of PEGs and PF6- as well as ethoxy/hydroxyl oxygens of PEGs and the C2-H of bmim+ is proposed to be responsible for the unusual outcomes. Fluorescence probe responses are shown to be adequately predicted by a four-parameter simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) model. Unusually altered physicochemical properties are demonstrated to be the key feature of the "hybrid green" PEG+IL systems.

Addition of yttrium into HfO2 films: Microstructure and electrical properties

The cubic phase of HfO2 was stabilized by addition of yttrium in thin films grown on Si∕SiO2 by metal-organic chemical vapor deposition. The cubic phase was obtained for contents of 6.5at.% Y or higher at a temperature as low as 470°C. The complete compositional range (from 1.5to99.5at.% Y) was investigated. The crystalline structure of HfO2 was determined from x-ray diffraction, electron diffraction, and attenuated total-reflection infrared spectroscopy. For cubic films, the continuous increase in the lattice parameter indicates the formation of a solid-solution HfO2–Y2O3. As shown by x-ray photoelectron spectroscopy, yttrium silicate is formed at the interface with silicon; the interfacial layer thickness increases with increasing yttrium content and increasing film thickness. The dependence of the intrinsic relative permittivity εr as a function of Y content was determined. It exhibits a maximum of ∼30 for ∼8.8at.% Y. The cubic phase is stable upon postdeposition high-temperature annealing at 900°C under NH3.

Stability and phase behavior of the poly(ethylene oxide)–urea complexes prepared by electrospinning

The poly(ethylene oxide)–urea binary system forms a stable (α) complex that can be melt-quenched into a mixture of urea and a second (β) complex with a different stoichiometry. Our results confirm that this mixture is metastable, but that the β–α solid–solid transition is much slower than previously reported. In contrast with the melt-quenched mixture, we observe for the first time that the pure β complex, prepared by electrospinning, is thermodynamically stable up to its melting temperature. This melting is incongruent and leads to the formation of the crystalline α complex and liquid PEO. A phase diagram is drawn over the complete composition range and allows interpreting the formation of the various out-of-equilibrium mixtures observed experimentally. This work also demonstrates an interesting new possibility of electrospinning: the direct preparation of thermodynamically stable compounds that are otherwise inaccessible because of the formation of kinetically frozen products.

K-Ar geochronology of basalt petrogenesis, Newer Volcanic Province, Victoria

The largest component of the basaltic Newer Volcanic Province of Victoria, Australia, the Western Plains subprovince, comprises extensive tholeiitic to alkalic lava flows and pyroclastics. The subprovince is subdivided into eastern and western sectors with distinctive Sr isotopic signatures; the isotopic discontinuity corresponds to an underlying Paleozoic tectonic boundary. Fifty-one new K–Ar ages plus previously published results encompass the geographic, lithological and isotopic variants of the subprovince, and are used to date extensive flow units, provide time calibration of regolith mapping units, and to compile eruptive and petrogenetic histories. The onset of volcanism at 4.6 Ma, the peak of activity at 3.0–1.8 Ma, and the progression from tholeiitic to alkalic compositions towards the present day are subprovince-wide, indicating that the basis of activity is independent of the lithospheric substrate. Local activity appears to have little pattern: some subareas have a conservative aspect, erupting similar tholeiites over much of the time span of the field; others show the complete range of lithological and isotopic composition. Peak activity (3.0–1.8 Ma) produced the maximum range of rock and isotopic compositions erupted subprovince-wide: the western sector has alkalic basalt to tholeiite (87Sr/86Sr 0.7041–0.7044), and the eastern sector transitional basalt to basaltic icelandite with much larger isotopic variation (87Sr/86Sr 0.7042–0.7055). In contrast to this apparently erratic behaviour, plots of 87Sr/86Sr vs time reveal a coherent system with the distinct eastern and western sectors expressing parallel isotopic change, a progressive decline in 87Sr/86Sr as magma compositions change from tholeiitic to more alkalic. Potential explanations, mantle chemical heterogeneity and crustal contamination, are examined in the light of chronological constraints. The tholeiitic to alkalic progression is analogous to that of oceanic islands and considered characteristic of intraplate volcanism; it implies that the most recent phase of Cenozoic volcanic activity in Victoria is coming to a close.

Continuous Alloy-Composition Spatial Grading and Superbroad Wavelength-Tunable Nanowire Lasers on a Single Chip

By controlling local substrate temperature in a chemical vapor deposition system, we have successfully achieved spatial composition grading covering the complete composition range of ternary alloy CdSSe nanowires on a single substrate of 1.2 cm in length. Spatial photoluminescence scan along the substrate length shows peak wavelength changes continuously from approximately 500 to approximately 700 nm. Furthermore, we show that under strong optical pumping, every spot along the substrate length displays lasing behavior. Thus our nanowire chip provides a spatially continuously tunable laser with a superbroad wavelength tuning range, unmatched by any other available semiconductor-based technology.