Mixed Liquids Research Articles

Development and construction of a cost-effective non-contact instrument for measuring the dielectric constant of liquids.

This research presents the development and construction of a cost-effective instrument, designed to measure the dielectric constant of liquids by employing a non-contact method that relies on determining the capacitance of a cell containing the liquid and its relaxation frequency. This instrument utilizes an astable multi-vibrator integrated with a resistance-capacitor network, in which the cell housing the liquid of interest functions as a capacitor element of the oscillator. The frequency of the generated oscillations is meticulously recorded using a seven-digit frequency meter with a resolution of 1Hz. The cell was filled with an array of pure liquids with known dielectric constants, and their frequencies were subsequently recorded at ambient temperatures. An equation was fitted to the frequency-dielectric constant curve, which was used as a calibration equation to determine the dielectric constant of subsequent liquids. In addition to pure liquids, dielectric constants for solvent mixtures of varying mole fractions were also calculated using the previously established calibration equation. Our results demonstrated excellent frequency stability of the instrument, and the obtained dielectric constant values displayed significant consistency with both the experimental data and predictions made by computational methodologies. This suggests that the constructed instrument exhibits a high level of accuracy in measuring the dielectric constant of both pure and mixed liquids, establishing its potential utility in relevant research and industrial applications.

Estimating contact angle of pure and mixed liquids on smooth solid surfaces using dispersive-to-attractive surface energy ratio from PCP-SAFT model

This study introduces a novel methodology using the PCP-SAFT model and Young equation to estimate contact angles of pure and mixed liquids on solid surfaces. By considering the dispersion and non-dispersion contributions to the Helmholtz energy, our approach estimates the ratio of dispersion to total surface energy, that is crucial to predict contact angles. Comparing our results with literature data demonstrates high accuracy; the average absolute relative deviation (AARD) of 6.65% is achieved for estimating the ratio of dispersion surface tension to total surface tension of 13 liquids and 9.27% for estimating contact angle for 70 systems at room condition. Moreover, our model effectively captures the temperature and composition variations for binary mixtures on various surfaces, showing its applicability in understanding the wetting behavior. The PCP-SAFT model offers a promising tool for estimating the ratio of dispersion surface tension to total surface tension, required to estimate contact angle as an important measure of surface wetting.

Ultrastable fluorinated copolypeptide nanodroplets of loaded mixed liquids with low vaporization threshold

The expansion of ultrasound molecular imaging applications warrants a reduction in ultrasound contrast agent size and significant advancement in the in vivo stability of shell-stabilized bubbles. The shift from first to second-generation ultrasound contrast agents was marked by an improvement in stability as air was replaced by hydrophobic gases like perfluoropropane and sulfur hexafluoride. Further enhancements may be facilitated by focusing on strategies to retain the encapsulated gas within the ultrasound contrast agent shell despite extreme mechanical deformations. In this study, we developed a novel ultrasound contrast agent with a unique shell structure and a specially-formulated, low-boiling fluorinated liquid interior, resulting in superior stability during repeated and prolonged ultrasound-induced oscillations. Our ultra-stable nanodroplets can withstand sustained in vitro ultrasound exposure with minimal signal attenuation and can induce significant signal enhancement and delay in signal attenuation in the kidney, liver, and tumor tissues during in vivo experiments. Furthermore, encapsulating photosensitizers within these nanodroplets and leveraging photothermal effects could further augment the ultrasound imaging signal and verify its efficacy in tumor therapy. The creation of highly stable nanodroplets opens immense potential to augment the role of ultrasound in molecular imaging, therapy, and drug delivery.

Preparation of microelectrode based on molecularly imprinted monolith using ionic liquids as functional monomers for specific separation and enrichment of phenolic acids

Efficient and specific isolation and capture of phenolic acids (PAs) in complex samples is challenging due to its high polarity. In this study, combining the merits of porous monolith, ionic liquids, molecularly imprinted polymer and electroenhanced solid-phase microextraction (EE-SPME), a new sample pretreatment method was developed for the selective isolation and extraction of PAs. Using vanillic acid (VA) as template molecule, mixed ionic liquids including 1-allyl-3-methylimidazoliumbis[(trifluoromethy)sulfonyl]imide and N,N,N-trimethyl-1-(4-vinylphenyl)methanaminium chloride were chosen as dual functional monomers, a molecularly imprinted monolith-based microelectrode (MBM) was in-situ fabricated. Under the EE-SPME format, the extraction behaviors and specific recognition performance of MBM towards VA and its structural analogues were investigated in detail. Results revealed that the exertion of electric field during extraction period increased the imprinted factors from 1.57–1.77 to 1.87–2.23. Under the beneficial parameters, a sensitive and reliable approach for the quantification of PAs contents in water and fruit juice samples by the combination of MBM/EE-SPME with HPLC technique was developed. The achieved limits of detection ranging from 0.012 μg/L to 0.11 μg/L and 0.042 μg/L to 0.15 μg/L for waters and juices, respectively, and the recoveries with different spiked concentrations in actual sample were 83.1–110 %. In comparison with the existing approaches, the established method presented some characteristics in the analysis of PAs, such as simplicity, high cost-effectiveness, good anti-interference performance, satisfactory sensitivity and low consumption of solvent.

Surface polarity modulation enables high-performance polyamide membranes for separation of polar/non-polar organic solvent mixtures

Achieving highly selective separation of organic mixtures is crucial to modern fine chemicals and pharmaceutical industries. The membrane-based organic solvent reverse osmosis (OSRO) technology is expected to break through this barrier. The key to achieving the separation of organic mixed liquids is to design the OSRO membrane as needed based on the physical and chemical properties of the target separation solvent. However, this poses a huge challenge to traditional OSRO membranes. In this work, we report composite polyamide (PA) OSRO membranes with ultrahigh polar/non-polar organic mixture selectivity. The surface polarity of the composite PA membrane is increased by coating a layer of Fe3+/tannic acid (Fe3+/TA) layer on the surface of the PA membrane. The enhanced surface polarity increases the interaction difference between polar and non-polar solvents and the membrane. And a polarization layer is formed on the membrane surface, which weakens the concentration polarization effect on the membrane surface. Under high-concentration feed liquid (the mass ratio of methanol/hexane is 7:3), the separation factor of the prepared membrane reaches 218, which is the highest value of all OSRO membranes reported so far. For the first time, we establish a partial flux analysis for the OSRO process. This analysis unravels the pressure, concentration dependence, and sensitivity of separation performance. It provides novel insights into the design of high-performance OSRO membranes.

Molecular dynamics simulation study of sodium ion structure & dynamics in water in ionic liquids electrolytes using 1-butyl-3-methyl imidazolium tetrafluoroborate and 1-butyl-3-methyl imidazolium hexafluorophosphate

In this paper, we have performed an all-atom molecular dynamics simulation to understand the structure and dynamics of Na+ ions in water mixed Ionic liquids (Water in Ionic liquid). Two ionic liquid (IL) systems consist of (1) 1-butyl-3-methylimidazolium [BMIM] tetrafluoroborate [BF4] and (2) 1-butyl-3-methylimidazolium [BMIM] hexafluorophosphate [PF6] were considered in this work. We understand various inter-molecular structures and dynamic and thermodynamic behaviours of Na+ ions in the water-mixed IL systems. The water (H2O) mole fractions (x) varied from 0.33 to 0.71. The neat ILs [BMIM][BF4] and [BMIM][PF6] pairwise radial distribution functions show a decrease with an increase in x. The [BMIM][PF6] exhibits a strong coordination structure with Na+ ions across the entire range of x values. The rdf between the pairs of Na+-[PF6] presents a significant interaction compared to Na+ and [BF4]. The Na + ions manifested greater coordination with H2O In H2O-[BMIM][PF6] compared to H2O-[BMIM][BF4]. The self-diffusion coefficient (D) values of Na + ions increase with the rise in x in both ILs. The D values of Na + ions are 10-fold higher in [BMIM][BF4] than [BMIM][PF6]. The ionic conductivity values are higher for [BMIM][BF4]. Overall, this paper unveils molecular-level insights for understanding the behavior of Na+ ions in the water in ionic liquid systems.

Ultrafast self-transportation and efficient separation of organic droplets on semi-conical asymmetric structure

Manipulating oil droplets in an aqueous solution is highly desirable for organic multiphase liquid separation. Despite substantial works in the realm of organic multiphase liquid manipulation and separation, the ultrafast transportation and efficient and precise separation of these liquids, especially those with varied surface tensions, encounters significant challenges due to little driving forces. To address this issue, a semi-conical structure with pine-needlelike features and incorporated wedge-shaped grooves is fabricated, which could support the ultrafast transport and separation of organic droplets. For pre-wetted superhydrophobic surfaces, organic liquids with lower surface tension can be transported at a speed of 305.6 mm/s. The Laplace pressure difference caused by the conical structure determines the direction of transport of organic liquids, and the capillary force caused by flat wedge-shaped grooves increases the transport speed of organic droplets on the surface. Based on the characteristics of “differential” transportation and directional transportation, the separation of mixed organic liquids is realized. This biomimetic design concept will pave a path for microfluidics, liquid manipulation, and the separation of various organic liquids.

In English

The temperature and interfacial behaviors of individual and mixed liquids are of importance from a practical point of view because changes in the phase state of compounds with decreasing temperature could lead to negative effects (e.g., frost damage of porous materials). However, the use of certain mixtures may prevent these negative effects due to the colligative properties of the solutions (cryscopic effects, CE) that lead to several effects including relative lowering of vapor pressure, boiling point elevation, and freezing point depression (FPD). Confined space effects (CSE) also leading to the freezing point depression can affect the colligative properties of liquid mixtures with respect to FPD. One could assume that for some systems with certain FPD due to CE for bulk solutions, there is no additivity (synergetic effect) of CSE and CE, but for others, the opposite results could be. To elucidate these interfacial phenomena, a set of liquid mixtures bound to different adsorbents could be studied using low-temperature NMR spectroscopy. The solutions included acids, bases, and salts as solutes, some liquids (e.g., dimethylsulfoxide, acetonitrile, n-decane) as co-sorbates and others (e.g., CDCl3, CCl4) as dispersion media. The adsorbents included various porous and highly disperse silicas, fumed alumina, carbons (activated carbons, graphene oxides), and porous polymers. So wide ranges of the systems studied could allow one a deeper insight into competitive or additive CSE and CE influencing the interfacial and temperature behaviors of bound liquids. The results of this analysis are of interest from both practical and theoretical points of view.

Highly Conductive Doped Fluoride Solid Electrolytes with Solidified Ionic Liquid to Enable Reversible FeF3 Conversion Solid State Batteries

AbstractSolid‐state lithium metal batteries based on fluorinated solid electrolytes have attracted attention due to their safety and stability advantages. However, the fluoride solid electrolytes face the problem of relatively low Li‐ion conductivity due to the lacking of suitable structural prototypes and their corresponding modulation modes. In this work, a chlorine‐doped fluoride solid electrolyte Li3AlF5.87Cl0.13 is developed with high ionic conductivity by thermal fluorination and weak chlorination of mixed ionic liquids. The Cl anion is doped into the cryolite‐like open framework structure, and the electrolyte particle boundaries are decorated by solidified thin‐layer (≈2 nm) ionic liquid. Both the bulk and interface modifications enable the improvement of Li‐ion conductivity to 2 × 10−4 S cm−1 at 30 °C, which is the highest level among fluoride solid electrolytes. The Li3AlF5.87Cl0.13 with residual solidified ionic liquid shows the excellent stability of interface contact with Li metal, and the corresponding Li symmetric cell exhibits a small overvoltage (≈100 mV) with outstanding cycle life (at least 500 h). For the first time, a conversion‐type solid‐state Li/FeF3 battery is developed based on this fluoride electrolyte, delivering a reversible capacity as high as 430 mAh g−1. The existence of natural F‐rich interface promotes the conversion reaction reversibility of FeF3 cathode.

Neural network-based prediction of auto-ignition temperature of ternary mixed liquids

Auto-ignition temperature (AIT) is one of the crucial exponents in the design of fire and explosion safety measures. Therefore, in this study, quantitative structure-property relationship approach was used to predict the AIT of ternary hybrid liquids based on molecular structure information. The optimal molecular descriptors were calculated and filtered using Mordred software. Twelve mixing rules were proposed for calculating molecular descriptors of mixtures. A prediction model for the AIT value of binary liquid mixtures was developed, validated and evaluated using a back propagation neural network (BPNN) and a one-dimensional convolutional neural network (1DCNN). The relative contribution and positive and negative correlations between individual molecular descriptors and AIT in the model were interpreted using the shapley additive explanations method. The results show that BPNN and 1DCNN models using mixing rule 1 have the best fitting ability, stability and prediction ability. The determination coefficient of the BPNN and 1DCNN models in the training set were 0.996 and 0.992, the root mean square errors were 3.613 °C and 5.284 °C, the mean absolute errors were 2.483 °C and 4.144 °C, the nash efficiency coefficient was 0.996 and 0.992, respectively, the willmott index was 0.999 and 0.998. and the values of the top three molecular descriptors of relative contribution, SssCH2, SsOH and SsCH3, were negatively correlated with the AIT values. The BPNN and 1DCNN models provide an accurate and reliable method for predicting ternary mixing liquid AIT.

Deep eutectic solvent mixed ionic liquids achieve highly enhanced electromagnetic wave absorption and mechanical properties

The network interactions between ionic liquids and deep eutectic solvents impart exceptional electromagnetic wave absorption and mechanical properties to the gel.

Superhydrophilic-superhydrophobic integrated system based on copper mesh for continuous and efficient oil-water separation.

In petroleum, petrochemicals, metallurgy, and chemical industries, a significant volume of oily wastewater is unavoidably generated throughout the production processes. This not only harms the environment but also brings about diverse adverse effects on social and economic progress. In this study, copper mesh separation membranes exhibiting superhydrophobicity and superhydrophilicity/underwater superoleophobicity were fabricated through in situ oxidation, chemical vapor deposition, and other physical and chemical modification techniques. Moreover, copper meshes possessing contrasting wetting properties were incorporated into a system combining superhydrophilicity and superhydrophobicity enabling the continuous and efficient separation of mixed oil-water liquids. The separation efficiency of both the superhydrophobic and superhydrophilic membranes surpassed 99.0% and remained above 97.0% after 15 days of continuous use, showcasing the remarkable effectiveness and durability of the integrated system design. This research presents a straightforward and cost-effective design approach for the large-scale treatment of oily wastewater in industrial settings, which is expected to have extensive applications in practical production.

A processable ionogel with thermo-switchable conductivity.

We report an ionogel with thermo-switchable conductivity and high processability based on physical self-assembly of poly(styrene-b-ethylene oxide-b-styrene) (PS-PEO-PS) in mixed ionic liquids composed of thermo-responsive 1,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide and polymerizable 1-(4-vinylbenzyl)-3-butylimidazolium bis(trifluoromethylsulfonyl)imide, and subsequent chemical crosslinking of the polymerizable component.

Enhanced ionic conductivity in block copolymer electrolytes through interfacial passivation using mixed ionic liquids.

We present a strategic approach for enhancing the ionic conductivity of block copolymer electrolytes. This was achieved by introducing mixed ionic liquids (ILs) with varying molar ratios, wherein the imidazolium cation was paired with either tetrafluoroborate (BF4) anion or bis(trifluoromethylsulfonyl)imide (TFSI) anion. Two polymer matrices, poly(4-styrenesulfonate)-b-polymethylbutylene (SSMB) and poly(4-styrenesulfonyl (trifluoromethanesulfonyl)imide)-b-polymethylbutylene (STMB), were synthesized for this purpose. All the SSMB and STMB containing mixed ILs showed hexagonal cylindrical structures, but the type of tethered acid group significantly influenced the interfacial properties. STMB electrolytes demonstrated enhanced segregation strength, which was attributed to strengthened Coulomb and hydrogen bonding interactions in the ionic domains, where the ILs were uniformly distributed. In contrast, the SSMB electrolytes exhibited increased concentration fluctuations because the BF4 anions were selectively sequestered at the block interfaces. This resulted in the effective confinement of imidazolium TFSI along the ionic domains, thereby preventing ion trapping in dead zones and facilitating rapid ion diffusion. Consequently, the SSMB electrolytes with mixed ILs demonstrated significantly improved ionic conductivities, surpassing the expected values based on the arithmetic average of the conductivities of each IL, whereas the ionic conductivity of the STMB was aligned with the expected average. The methodology explored in this study holds great promise for the development of solid-state polymer electrolytes.

Spontaneous Separation of Immiscible Organic Droplets on Asymmetric Wedge Channels with Hierarchical Microchannels.

Spontaneous separation of immiscible organic droplets has substantial research implications for environmental protection and resource regeneration. Compared to the widely explored separation of oil-water mixtures, there are fewer reports on separating mixed organic droplets on open surfaces due to the low surface tension differences. Efficient separation of mixed organic liquids by exploiting the rapid spontaneous transport of droplets on open surfaces remains a challenge. Here, through the fusion of inspiration from the fast droplet transport capability of Sarracenia trichome and the asymmetric wedge channel structure of shorebird beaks, this work proposes a spine with hierarchical microchannels and wedge channels (SHMW). Due to the synergistic effect of capillary force and asymmetric Laplace force, the SHMW can rapidly separate mixed organic droplets into two pure phases without requiring additional energy. In particular, the self-spreading of the oil solution on the open channel surface is utilized to amplify the surface energy difference between two droplets, and SHMW achieves the pickup of oil droplets floating on the surface of the organic solution. The maximum separation efficiency on 3-SHMW can reach 99.63%, and it can also realize the antigravity separation of mixed organic droplets with a surface tension difference as low as 0.87 mN·m-1. Furthermore, SHMW performs controllable separation, oil droplet pickup, and continuous separation and collection of mixed organic droplets. It is expected that this cooperative structure composed of hierarchical microchannels and wedge channels will be realized in resource recovery or chemical reactions in industrial production processes.

Application of Transformer Oil and Biodegradable Ester Mixtures as Insulation for High-Voltage Equipment

Synthetic and natural esters as insulating fluids for high voltage equipment have been a focus of much research, especially in the last two decades. This is due to the fact that, unlike mineral oil, ester fluids are biodegradable, non-toxic, safe for the environment and human health, produced from renewable raw materials, and feature high fire resistance. Despite the fact that commercially available ester fluids having excellent insulating properties are offered in the market, both transformer manufacturers and operators are not yet ready for mass-scale transition to the use of biodegradable ester dielectric fluids. In addition, since there is a huge amount of electrical equipment filled with mineral oil, mass-scale replacement of this oil with ester dielectric fluids will be extremely expensive for power companies. A suitable way for making a shift from oil to esters can be partial replacement of mineral oil with ester fluids (for example, topping up during repairs) or complete replacement of mineral oil with biodegradable esters. Whatever of these options is implemented, there will be a mixture of two insulating fluids inside of the equipment. Therefore, specialists intensely study the characteristics and behavior of insulating mixtures based on mineral oil and other dielectric fluid (synthetic ester, natural ester or silicone fluid). The article presents a review of the latest advances in the investigations of mixtures consisting of mineral oil and other dielectric fluids, including the studies of their properties. Problems associated with the operation of equipment in the case of its filling with mixed liquids are discussed.

Highly Processable Ionogels with Mechanical Robustness

AbstractCurrently, the increasing needs of conductive ionogels with intricate shapes and high processability by individual requirements of next‐generation flexible electronics constitute significant challenges. Here, the design of highly processable ionogels is reported with mechanical robustness by self‐assembly of a common triblock copolymer into a precursor in functional mixed ionic liquids (ILs) containing conductivity‐enhancing and polymerizable strength‐enhancing components. The subsequent in situ polymerization of the precursor forms physical‐co‐chemical cross‐linked networks, in which the entanglement between physical and chemical cross‐linked networks and microphase separation give rise to mechanical robustness of as‐fabricated ionogel. The viscosity of the self‐assembled precursor can be rationally tuned, which makes the fabrication process compatible with diverse technologies including inkjet printing, spray coating, and 3D printing. By virtue of highly processable capability of the designed ionogels, an auxetic‐structured ionogel can be easily generated using 3D printing, which exhibits greatly improved sensitivity and thus is able to monitor tiny deformations. This study that relies on designing functional mixed ILs as the dispersion phase rather than focusing on synthesizing new‐type polymers establishes a new route for versatile and programmable fabrication of high‐performance ionogels for broader applications.

Mechanism of mixed alkali effect in silicate glass/liquid: Pathway and network analysis

The mixed alkali effect in silicate glass/liquid causes two anomalies: a decrease in the self-diffusivity of alkali ions and a decrease in shear viscosity. Previous studies using molecular dynamics (MD) simulations proposed that the decrease in diffusivity of alkali ions is the result of pathway blocking. However, the actual statistics of the pathway have never been presented. In this study, we revisited the mixed alkali effect in sodium–potassium silicate glass/liquid using MD simulations. The distinct part of van Hove's function indicates that site exchange between different alkali species is significantly slower than between the same species. By introducing simplex sphere analysis and its cluster statistics with varying compositions, we clarified the pathway disconnection caused by alkali mixing. Moreover, we analyzed the geometry and topology of the corner-shared network of the SiO4 tetrahedra precisely. Both the geometry and topology change linearly with advancing alkali substitution, whereas the calculated shear viscosities have a minimum in the mixed alkali composition. Consequently, a method to quantitatively analyze the changes in relaxation dynamics is required to clarify the viscosity anomaly in mixed alkali liquids.

芽胞形成細菌に対するオゾンウルトラファインバブル混合液の殺菌効果

In this study, antimicrobial effect of mixed ultra-fine bubble liquids on two types of bacteria; spore-forming bacteria (Bacillus subtilis var. natto) and the environmental bacteria was investigated. We used ultrapure water (UPW), mixed ultra-fine bubble water (UFB), mixed ultra-fine ozone-rich bubble water (UFORB), and water containing ozone (OZ). Viable bacteria count (VBC) of UFB agreed with that of UPW within the experimental errors (p < 0.05). Low VBC (High effect) of UFORB and OW exhibited on B. subtilis var. natto. Moreover, complete sterilization of UFORB was obtained on the environmental bacteria. For discussing the experimental results, we observed number density against particle diameter, effect of dilution and elapsed time after stopped the ultra-fine bubble generator. Difference between UFB and UFORB exhibited in case of distribution of particle diameter (peak diameter and averaged diameter). The bactericidal effect on B. subtilis var. natto persisted after 360 min (6 h), but disappeared after 1440 min (24 h). On the other hand, the bactericidal effect against the environmental bacteria was high even after 1440 min (24 h).

A Review of Working Fluids and Flow State Effects on Thermal Performance of Micro-Channel Oscillating Heat Pipe for Aerospace Heat Dissipation

A MCOHP (micro-channel oscillating heat pipe) can provide lightweight and efficient temperature control capabilities for aerospace spacecraft with a high power and small size. The research about the heat flow effects on the thermal performance of MCOHPs is both necessary and essential for aerospace heat dissipation. In this paper, the heat flow effects on the thermal performance of MCOHPs are summarized and studied. The flow thermal performance enhancement changes of MCOHPs are given, which are caused by the heat flow work fluids of nano-fluids, gases, single liquids, mixed liquids, surfactants, and self-humidifying fluids. The use of graphene nano-fluids as the heat flow work medium can reduce the thermal resistance by 83.6%, which can enhance the maximum thermal conductivity by 105%. The influences of gravity and flow characteristics are also discussed. The heat flow pattern changes with the work stage, which affects the flow mode and the heat and mass transfer efficiency of OHP. The effective thermal conductivity varies from 4.8 kW/(m·K) to 70 kW/(m·K) when different gases are selected as the working fluid in OHP. The study of heat flow effects on the thermal performance of MCOHPs is conducive to exploring in-depth aerospace applications.