Ionic Fluids Research Articles

Application of the significant structure theory for the viscosity modeling of ionic fluids

The present work introduces the application of a modified significant structure theory (SST) in order to obtain improved representations of the dynamic viscosity of several representative last-generation ionic fluids: pure ionic liquids (ILs) and deep eutectic solvents (DESs). The activated-state variables present in the resulting SST-based model were related to well-known thermodynamic potentials (residual internal energy, liquid and solid molar volumes) which in turn were estimated from two simple cubic equations of state of the van der Waals type: Soave-Redlich-Kwong or Peng-Robinson. The modifications introduced to the SST approach were successfully verified during the correlation and prediction of experimental dynamic viscosities of 3 families of imidazolium-based ILs ([CXmim][BF4], [CXmim][PF6] and [CXmim][Tf2N]), one pyridinium-based IL ([b3mpy][BF4]), one pyrrolidinium-based IL ([P14][Tf2N]), one ammonium-based IL ([N1114][Tf2N]) and four ILs having nonfluorinated anions ([dmim][MeSO4], [bmim][EtSO4], [bmim][Ac] and [b3mpy][dca]) over a temperature range varying from 273.15 to 438.15 K and at pressures from 1 to 3,000 bar We also considered three archetypal choline chloride-based DESs for model validation: Reline, Ethaline and Glyceline within a temperature range varying from 293.15 to 373.15 K and at pressures from 1 to 1,000 bar

Ionic fluids out of equilibrium: electrodeposition, dissolution, electron transfer, driving forces: general discussion.

Ionic fluids out of equilibrium: electrodeposition, dissolution, electron transfer, driving forces: general discussion.

A fabrication strategy for millimeter-scale, self-sensing soft-rigid hybrid robots.

Soft robots typically involve manual assembly of core hardware components like actuators, sensors, and controllers. This increases fabrication time and reduces consistency, especially in small-scale soft robots. We present a scalable monolithic fabrication method for millimeter-scale soft-rigid hybrid robots, simplifying the integration of core hardware components. Actuation is provided by soft-foldable polytetrafluoroethylene film-based actuators powered by ionic fluid injection. The desired motion is encoded by integrating a mechanical controller, comprised of rigid-flexible materials. The robot's motion can be self-sensed using an ionic resistive sensor by detecting electrical resistance changes across its body. Our approach is demonstrated by fabricating three distinct soft-rigid hybrid robotic modules, each with unique degrees of freedom: translational, bending, and roto-translational motions. These modules connect to form a soft-rigid hybrid continuum robot with real-time shape-sensing capabilities. We showcase the robot's capabilities by performing object pick-and-place, needle steering and tissue puncturing, and optical fiber steering tasks.

Numerical study on solar trough collectors: Optimizing heat transfer with ternary nanoparticles in ionic base fluid and spinning tube fins

The present study investigates the simultaneous influence of ternary nanoparticles in an ionic-based liquid ([EMIM][BF4]) within a parabolic solar trough collector (PTC) tube for heat conveyance. Various types of fins are considered on the inner surface of the receiver tube to enhance turbulence in the flow, thereby improving heat flux distribution and reducing issues related to thermal stress. Using ANSYS 23 Fluent, four cases are simulated, including three with differently structured fins and one representing a traditional PTC tube without fins. Hybrid nanofluids with 1 % volume content, comprising copper oxide, graphene oxide, and aluminum oxide mixed with the ionic base liquid, are examined. The tubes, along with the fins, undergo rotation with spinning rates ranging from 0 rad/s to 15 rad/s, while the flow rate of the working medium varies from 0.15kg/s to 0.60kg/s. Improvements of Nusselt number and thermal performance factor are found as 55.45 %, and 47.45 %, respectively, for Nanofluid-6 than Nanofluid-1 at Re = 4739.30. Enhancement for thermal efficiency is 22.50 % for Case-1 with Nanofluid-6 at 15 rad/s tube spinning speed than 0 rad/s spinning speed. Thus, this study provides crucial insights for selecting the most effective modified model based on its thermal performance, helping to enhance both design and operational efficiency.

Suitability of Test Procedures for Determining the Compatibility of Seal Materials with Ionic Hydraulic Fluids.

The compatibility of seal materials with the working fluid is crucial for the flawless, energy-saving, environmentally sustainable, and safe operation of any technical system. This is especially true for hydraulic systems operating under high operating pressure. The problem of materials compatibility comes into play when either a new type of seal material or a new type of fluid comes into use. The paper discusses the research findings regarding material compatibility testing of new high-tech ionic hydraulic fluids with commonly used seal materials. Due to the completely different chemical composition of these new fluids compared to the classical mineral-based oil, for these fluids, there are no standardized testing procedures. In these cases, we can only lean on the Standards that apply to classical fluids, which can lead to incorrect results. In the forefront of the paper is the discrepancy between the results obtained by the standardized test, and the test under real operating conditions. FKM, an excellent material for seals, proved to be the most suitable in the case of using ionic hydraulic fluid, according to a standardized test. However, it failed in the comparison test under real operating conditions, as the cylinder leaked. NBR seals proved to be a better solution.

Good practice with fluid management in operative hysteroscopy.

Hysteroscopic surgery requires a balance of continuous controlled irrigation and aspiration to distend the endometrial cavity to a degree that provides the clear and stable visual environment necessary for diagnostic and therapeutic procedures. Whereas the preferred distending solution should be isotonic and isonatremic, radiofrequency (RF) electrosurgery with monopolar instrumentation can only be performed with non-ionic (hyponatremic) solutions. Absorption of as little as 500 mL and certainly more than 1000 mL of non-ionic solutions can result in fluid overload and/or dilutional hyponatremia with potentially serious adverse effects under certain conditions and patient characteristics. Both hysteroscopic RF electrosurgery with bipolar instrumentation and electro-mechanical morcellation and aspiration systems use isotonic and isonatremic solutions. Depending on the clinical context, absorption of more than 1500 mL of isonatremic solutions can also result in serious adverse effects. Automated fluid management systems are preferred and recommended, and surgeons should aim to maintain the maximum allowable intravasation of distending media below 1000 and 1500 mL for non-ionic and ionic fluids, respectively.

Highly tough, crack‐resistant and self‐healable piezo‐ionic skin enabled by dynamic hard domains with mechanosensitive ionic channel

AbstractRobust and reliable piezo‐ionic materials that are both crack resistant and self‐healable like biological skin hold great promise for applications inflexible electronics and intelligent systems with prolonged service lives. However, such a combination of high toughness, superior crack resistance, autonomous self‐healing and effective control of ion dynamics is rarely seen in artificial iontronic skin because these features are seemingly incompatible in materials design. Here, we resolve this perennial mismatch through a molecularly engineered strategy of implanting carboxyl‐functionalized groups into the dynamic hard domain structure of synthesized poly(urethane‐urea). This design provides an ultra‐high fracture energy of 211.27 kJ m−2 that is over 123.54 times that of tough human skin, while maintaining skin‐like stretchability, elasticity, and autonomous self‐healing with a 96.40% healing efficiency. Moreover, the carboxyl anion group allows the dynamic confinement of ionic fluids though electrostatic interaction, thereby ensuring a remarkable pressure sensitivity of 7.03 kPa−1 for the tactile sensors. As such, we successfully demonstrated the enormous potential ability of this skin‐like piezo‐ionic sensor for biomedical monitoring and robotic item identification, which indicates promising future uses in flexible electronics and human–machine interactions.

Shear‐driven flow of an ionic fluid in a narrow vertical channel under a Hall electric field

AbstractThis paper focuses on demonstrating the shear‐driven convective flow of an ionic optically thin fluid in a narrow channel formed by two vertical parallel plates subject to a Hall electric field. The Hall electric field induces Hall currents, amending the flow dynamics of the ionic fluid. The setup involves a stationary left wall and a right wall that either undergoes impulsive motion (IM) or accelerated motion (AM), which initiates the fluid flow. A unified closed‐form solution for flow‐regulating equations is derived by harnessing the Laplace transform (LT) approach. The upshots of cardinal parameters on the velocity components and temperature distributions, shear stresses, and rate of heat transfer (RHT) are elucidated via graphics for both IM and AM scenarios. The graphs reveal that an intensification in the Hall parameter notably boosts the velocity components in both IM and AM cases. The primary and secondary velocities are consistently higher for IM than AM. The magnitude of shear stresses at the moving wall is always greater for IM than AM. Additionally, the shear stresses at the moving wall are notably greater for IM than AM, and the RHT at the moving wall reduces as the radiation parameter amplifies. The significant findings of this research have potential applications in electromagnetic propulsion systems, like plasma or ion thrusters, commonly employed in propelling spacecraft.

A Review of Ionic Liquids and Their Composites with Nanoparticles for Electrochemical Applications

The current study focuses on reviewing the actual progress of the use of ionic liquids and derivatives in several electrochemical application. Ionic liquids can be prepared at room temperature conditions and by including a solution that can be a salt in water, or a base or acid, and are composed of organic cations and many charge-delocalized organic or inorganic anions. The electrochemical properties, including the ionic and electronic conductivities of these innovative fluids and hybrids, are addressed in depth, together with their key influencing parameters including type, fraction, functionalization of the nanoparticles, and operating temperature, as well as the incorporation of surfactants or additives. Also, the present review assesses the recent applications of ionic liquids and corresponding hybrids with the addition of nanoparticles in diverse electrochemical equipment and processes, together with a critical evaluation of the related feasibility concerns in different applications. Those ranging from the metal-ion batteries, in which ionic liquids possess a prominent role as electrolytes and reference electrodes passing through the dye of sensitized solar cells and fuel cells, to finishing processes like the ones related with low-grade heat harvesting and supercapacitors. Moreover, the overview of the scientific articles on the theme resulted in the comparatively brief examination of the benefits closely linked with the use of ionic fluids and corresponding hybrids, such as improved ionic conductivity, thermal and electrochemical stabilities, and tunability, in comparison with the traditional solvents, electrolytes, and electrodes. Finally, this work analyzes the fundamental limitations of such novel fluids such as their corrosivity potential, elevated dynamic viscosity, and leakage risk, and highlights the essential prospects for the research and exploration of ionic liquids and derivatives in various electrochemical devices and procedures.

Characterizing Hydrated Sulfates and Altered Phases in Jezero Crater Fan and Floor Geologic Units With SHERLOC on Mars 2020

AbstractThe Mars 2020 Perseverance rover has explored fluvio‐lacustrine sedimentary rocks within Jezero crater. Prior work showed that igneous crater floor Séítah and Máaz formations have mafic mineralogy with alteration phases that indicate multiple episodes of aqueous alteration. In this work, we extend the analyses of hydration to targets in the Jezero western fan delta, using data from the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) Raman spectrometer. Spectral features, for example, sulfate and hydration peak positions and shapes, vary within, and across the crater floor and western fan. The proportion of targets with hydration associated with sulfates was approximately equal in the crater floor and the western fan. All hydrated targets in the crater floor and upper fan showed bimodal hydration peaks at ∼3,200 and ∼3,400 cm−1. The sulfate symmetric stretch at ∼1,000 cm−1 coupled with a hydration peak at ∼3,400 cm−1 indicate that MgSO4·nH2O (2 < n ≤ 5) is a likely hydration carrier phase in all units, perhaps paired with low‐hydration (n ≤ 1) amorphous Mg‐sulfates, indicated by the ∼3,200 cm−1 peak. Low‐hydration MgSO4·nH2O (n = 1–2) are more prevalent in the fan, and hydrated targets in the fan front only had one peak at ∼3,400 cm−1. While anhydrite co‐occurs with hydrated Mg‐sulfates in the crater floor and fan front, hydrated Ca‐sulfates are observed instead at the top of the upper fan. Collectively, the data imply aqueous deposition of sediments with formation of salts from high ionic strength fluids and subsequent aridity to preserve the observed hydration states.

Phosphonium chloride-based deep eutectic solvents inhibit pathogenic Acanthamoeba castellanii belonging to the T4 genotype.

Herein, we investigated the anti-amoebic activity of phosphonium-chloride-based deep eutectic solvents against pathogenic Acanthamoeba castellanii of the T4 genotype. Deep eutectic solvents are ionic fluids composed of two or three substances, capable of self-association to form a eutectic mixture with a melting point lower than each substance. In this study, three distinct hydrophobic deep eutectic solvents were formulated, employing trihexyltetradecylphosphonium chloride as the hydrogen bond acceptor and aspirin, dodecanoic acid, and 4-tert-butylbenzoic acid as the hydrogen bond donors. Subsequently, all three deep eutectic solvents, denoted as DES1, DES2, DES3 formulations, underwent investigations comprising amoebicidal, adhesion, excystation, cytotoxicity, and cytopathogenicity assays. The findings revealed that DES2 was the most potent anti-amoebic agent, with a 94% elimination rate against the amoebae within 24h at 30°C. Adhesion assays revealed that deep eutectic solvents hindered amoebae adhesion to human brain endothelial cells, with DES2 exhibiting 88% reduction of adhesion. Notably, DES3 exhibited remarkable anti-excystation properties, preventing 94% of cysts from reverting to trophozoites. In cytopathogenicity experiments, deep eutectic solvent formulations and dodecanoic acid alone reduced amoebae-induced human brain endothelial cell death, with DES2 showing the highest effects. Lactate dehydrogenase assays revealed the minimal cytotoxicity of the tested deep eutectic solvents, with the exception of trihexyltetradecylphosphonium chloride, which exhibited 35% endothelial cell damage. These findings underscore the potential of specific deep eutectic solvents in combating pathogenic Acanthamoeba, presenting promising avenues for further research and development against free-living amoebae.

Analytical Investigation of Thermal Radiation Effects on Electroosmotic Propulsion of Electrically Conducting Ionic Nanofluid with Single-Walled Carbon Nanotube Interaction in Ciliated Channels

This study examines the behavior of single-walled carbon nanotubes (SWCNTs) suspended in a water-based ionic solution, driven by the combined mechanisms of electroosmosis and peristalsis through ciliated media. The inclusion of nanoparticles in ionic fluid expands the range of potential applications and allows for the tailoring of properties to suit specific needs. This interaction between ionic fluids and nanomaterials results in advancements in various fields, including energy storage, electronics, biomedical engineering, and environmental remediation. The analysis investigates the influence of a transverse magnetic field, thermal radiation, and mixed convection acting on the channel walls. The novel physical outcomes include enhanced propulsion efficiency due to SWCNTs, understanding the influence of thermal radiation on fluid behavior and heat exchange, elucidation of the interactions between SWCNTs and the nanofluid, and recognizing implications for microfluidics and biomedical engineering. The Poisson–Boltzmann ionic distribution is linearized using the modified Debye–Hückel approximation. By employing real-world approximations, the governing equations are simplified using long-wavelength and low-Reynolds-number approximation. Conducting sensitivity analyses or exploring the impact of higher-order corrections on the model’s predictions in recent literature might alter the results significantly. This acknowledges the complexities of the modeling process and sets the groundwork for further enhancement and investigation. The resulting nonlinear system of equations is solved through regular perturbation techniques, and graphical representations showcase the variation in significant physical parameters. This study also discusses pumping and trapping phenomena in the context of relevant parameters.

Phase behavior of ionic fluid in charged confinement: An associating polymer density functional theory study

AbstractWith the rapid advancement of the new energy industry, porous electrode materials and complex electrolytes have gained widespread usage. Electrolytes exhibit distinctive phase behavior when subjected to the combined influence of confined space and electric fields. However, the measurement and prediction of such phase behavior encounter significant challenges. Consequently, numerous theoretical tools have been employed to establish models for phase equilibrium calculations. Nevertheless, current research in this field has notable limitations and fails to address the confinement of space or complex polymer electrolytes. Considering these shortcomings, an associating polymer density functional theory (PDFT) was developed by modifying excess free energy. This study examines the phase behavior of electrolytes with various chain lengths within diverse confined slits, revealing that the confinement effect and fluid tail chains can narrow the phase diagram. Additionally, a linear correlation between the electric field strength and the phase equilibrium offset has been identified, and a quantitative relationship is derived. The results of this investigation contribute to a deeper comprehension of complex fluid phase behavior and guide the design of electrochemical devices.

Sustainable combination of ionic liquid and deep eutectic solvent for protecting and preserving of the protein structure: The synergistic interaction of enzymes and eco-friendly hybrid ionic fluids

Hybrid ionic fluids (HIFs) are one of the emerging and fascinating sustainable solvent media, a novel environment-friendly solvent for biomolecules. The HIFs have been synthesized by combining a deep eutectic solvent (DES), an ionic liquid (IL) having a common ion. The stability and activity of hen's egg white lysozyme (Lyz) in the presence of a recently designed new class of biocompatible solvents, HIFs have been explored by UV–visible, steady-state fluorescence, circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) along with dynamic light scattering (DLS) measurements. This work emphasizes the effect of DES synthesized by using 1:2 choline chloride and glycerol [Glyn], ILs (1-butly-3-methylimidazolium chloride [BMIM]Cl and choline acetate [Chn][Ac]) and their corresponding HIFs on the structure and functionality of Lyz. Moving forward, we also studied the secondary structure, thermal stability and enzymatic activity and thermodynamic profile of Lyz at pH = 7 in the presence of varying concentrations (0.1 to 0.5) M of [BMIM]Cl, [Chn][Ac] ILs, [Glyn] DES and [Glyn][BMIM]Cl (hybrid ionic fluid1) as well as [Glyn][Chn][Ac] (hybrid ionic fluid2). Spectroscopic results elucidate that ILs affect the activity and structural stability of Lyz, whereas the stability and activity are increased by DES and are maintained by HIFs at all the studied concentrations. Overall, the experimental results studied elucidate expressly that the properties of Lyz are maintained in the presence of hybrid ionic fluid1 while these properties are intensified in hybrid ionic fluid2. This work has elucidated expressly biocompatible green solvents in protein stability and functionality due to the alluring properties of DES, which can counteract the negative effect of ILs in HIFs.

Maser flares driven by isothermal shock waves

ABSTRACT We use 3D computer modelling to investigate the time-scales and radiative output from maser flares generated by the impact of shock waves on astronomical unit-scale clouds in interstellar and star-forming regions, and in circumstellar regions in some circumstances. Physical conditions are derived from simple models of isothermal hydrodynamic (single-fluid) and C-type (ionic and neutral fluid) shock waves, and based on the ortho-H2O 22-GHz transition. Maser saturation is comprehensively included, and we find that the most saturated maser inversions are found predominantly in the shocked material. We study the effect on the intensity, flux density, and duration of flares of the following parameters: the pre-shock level of saturation, the observer’s viewpoint, and the shock speed. Our models are able to reproduce observed flare rise times of a few times 10 d, specific intensities of up to 105 times the saturation intensity and flux densities of order 100(R/d)2 Jy from a source of radius R astronomical units at a distance of d kiloparsec. We found that flares from C-type shocks are approximately five times more likely to be seen by a randomly placed observer than flares from hydrodynamically shocked clouds of similar dimensions. We computed intrinsic beaming patterns of the maser emission, finding substantial extension of the pattern parallel to the shock front in the hydrodynamic models. Beaming solid angles for hydrodynamic models can be as small as 1.3 × 10−5 sr, but are an order of magnitude larger for C-type models.

Ionic Hydraulic Fluids and Seal-Material Compatibility

Manufacturers of hydraulic fluids invest a lot of effort and resources in improving their physico-chemical properties, with the goal of getting as close as possible to the properties of an ideal hydraulic fluid. It should be non- flammable, environmentally friendly, sustainable and should have excellent physical and chemical properties. After decades of development in the field of ionic liquids and the search for an ionic liquid suitable for use in hydraulic systems, ionic hydraulic liquids are now already in industrial use, especially on devices that operate in harsh and risky operating conditions. Since ionic hydraulic fluids are a completely new type of hydraulic fluid, one of the issues is their compatibility with the materials present in the hydraulic components, including all the seals. This paper refers to the process of testing the compatibility of hydraulic seal materials with different types of ionic hydraulic fluids according to the standardized percentages and recommendations, with emphasis on changes in the swell, shrinkage and hardness of the seals. The presented results are a useful guide for selecting suitable seal materials in case of using high-tech ionic hydraulic fluids.

Thermal stability and vapor-liquid equilibrium of aqueous solutions of choline and tetramethylammonium taurate

The thermal degradation of tetramethylammonium taurate and choline taurate and aqueous solutions of these compounds were examined. The thermal degradation products for each of the solid compounds are identified and the data show that the compounds lose less than 1 % of their mass when heating is below 85 °C for 10 h. However, it is difficult to distinguish between the degradation of the compounds and the loss of strongly retained water. The degradation products of the compounds in aqueous solution are also identified and a degradation pathway is proposed. Additionally, the vapor–liquid equilibrium of the compounds in aqueous solutions was measured and the data was fit to the non-random two-liquid (NRTL) model. The data indicate significant deviations from ideality as described by the activity coefficients of the solutions. The results provide insight into the selection of absorber stripping temperatures, the modeling of absorber columns that utilize aqueous ionic absorber fluids, and how these properties are impacted by different cations.

Speciation and dipole reorientation dynamics of glass-forming liquid electrolytes: Li[N(SO2CF3)2] mixtures of 1,3-propane sultone or tetrahydrothiophene-1,1-dioxide.

Recently new ionic fluids such as super-concentrated electrolyte solutions, solvate ionic liquids and deep eutectic solvents have attracted much attention in the field of liquid electrolytes for next-generation electrochemical devices and processes. The basic composition of these new ionic fluids is similar among them; a solvent and a large/excess amount of salt mixtures, though the solvent is sometimes a solid at ambient temperatures. Here, we found and demonstrated that LiTFSA (TFSA = (CF3SO2)2N-) mixtures with 1,3-propane sultone (PS) or tetrahydrothiophene-1,1-dioxide (SL) yield a homogeneous liquid at room temperature within a wide range of compositions. In order to clarify the uniquely high Li+ transference number in these mixtures, speciation and dipole reorientation dynamics were studied to provide evidence of large-size aggregate formation in these mixtures.

Ionic fluids at equilibrium: thermodynamics, nanostructure, phase behaviour, activity: general discussion.

Ionic fluids at equilibrium: thermodynamics, nanostructure, phase behaviour, activity: general discussion.

Concluding remarks: Dense ionic fluids: because sometimes, more is more.

It is a formidable challenge, and a distinct privilege, to provide the concluding remarks for this Faraday Discussion on Dense Ionic Fluids (DIFs). What follows is an inherently subjective distillation of the insights that have shaped our understanding of these complex systems over the last few days, with the goal of capturing the essence of the Discussion and providing suggestions for future investigations in this rapidly evolving field. DIFs are a fascinating class of electrolyte systems characterized by high ion concentrations in correlated domains. The multiscale nature of DIFs, and the challenges in connecting nanoscale phenomena to bulk properties, are discussed in the context of contemporary experimental and computational methods. Next, emerging trends are explored, and then the paper concludes by identifying promising future research directions.