Properties Of Pure Liquids Research Articles

OPLS/2020 Force Field for Unsaturated Hydrocarbons, Alcohols, and Ethers.

The OPLS all-atom force field was updated and applied to modeling unsaturated hydrocarbons, alcohols, and ethers. Testing has included gas-phase conformational energetics, properties of pure liquids, and free energies of hydration. Monte Carlo statistical mechanics (MC) calculations were used to model 60 liquids. In addition, a robust, automated procedure was devised to compute the free energies of hydration with high precision via free-energy perturbation (FEP) calculations using double annihilation. Testing has included larger molecules than in the past, and parameters are reported for the first time for some less common groups including alkynes, allenes, dienes, and acetals. The average errors in comparison with experimental data for the computed properties of the pure liquids were improved with the modified force field (OPLS/2020). For liquid densities and heats of vaporization, the average unsigned errors are 0.01 g/cm3 and 0.2 kcal/mol. The average error and signed error for free energies of hydration are both 1.2 kcal/mol. As noted before, this reflects a systematic overestimate of the hydrophobicity of organic molecules when the parametrization is done to minimize the errors for properties of pure liquids. Implications for the modeling of biomolecular systems with standard force fields are considered.

Nondestructive Evaluation of Fluid Characteristics using Compact Quarter-Mode SIW Resonator Sensor

Novel compact quarter-mode (QM) substrate integrated waveguide (SIW) resonator sensor based on dielectric properties developed. The sensor works on the principle of material perturbation of the cavity resonator. It operates in the broader range of ISM frequency band to characterize various properties of pure liquids, their admixtures, and soluble solids in the solution. The sensor is excited by a 50-ohm microstrip line. A Teflon tube passes through one end of the sensor to hold the material under test (MUT). The variations in the dielectric constant of the material under test shift the resonant frequency. The simulation result shows adequate shifts in resonant frequency and dielectric constant dependent. Thus, this feature of resonate frequency shift assists in determining the component concentration, adulteration, or various properties depending on specific calibration. The findings suggest that the proposed sensor can be successfully applied to determine properties with high precision using a very small amount of fluid in a novel non-destructive approach.

Photopyroelectric technique for the measurement of optical properties of pure liquids

Photopyroelectric technique, in the transmission configuration, was shown adequate for the measurement of the optical properties of pure liquids. The analytical scheme involves the scanning of the photopyroelectric signal as a function of the sample thickness. Optical absorption coefficients, at four wavelengths in the near infrared region (904 nm, 980 nm, 1310 nm, and 1550 nm), were measured for eight pure substances, distilled water and glycerol, among them. Strong optical absorption was obtained, particularly for pure liquids with a hydroxyl group in their molecular structure. In order to figure out about the influence of this chemical group on optical properties as function of the size of the molecule, optical absorption coefficient for a series of linear alcohols at 1550 nm was also measured.

Transport and optical properties of the binary liquid mixture containing 1,3-diaminopropane and alkyl acetates (C1-C4) at T= (303.15-318.15) K: experimental investigations and theoretical modelling

ABSTRACT Physicochemical properties of pure liquids and their liquid mixtures at different compositions and at different temperatures have a significant role in the optimisation of chemical processes. Present report involves the analysis of the physicochemical properties of 1,3-diaminopropane and alkyl acetate. The viscosity () and refractive index () of 1,3-Diaminopropane, 1,3-DAP (1), with alkyl acetates, AAc, (C1-C4) (2) were measured at different temperatures (T = 303.15 to 318.15 K) under the atmospheric pressure 0.1 MPa. Deviation in viscosity, , deviation in refractive index, , and excess Gibbs free energy of activation, for these binary mixtures were calculated from measured viscosity and refractive index data and fitted to Redlich-Kister polynomial equation (R.K.). The data were analysed in terms of the Graph theoretical approach (GTA) to study the interactions in binary mixtures. The values were also correlated by using Bloomfield and Dewan (BFD) model and various correlations. data were correlated by various relevant correlations.

Development and benchmarking of an open, self-consistent force field for proteins and small molecules from the open force field initiative.

Contemporary protein force fields model canonical proteins well, but parameters for covalently modified residues are challenging to develop. Additionally, protein-specific parameters are derived separately from those for small molecules, limiting the transferability of small molecule parameters to protein contexts. A flexible force field that provides self-consistent parameters for proteins and small molecules would advance research in drug design and molecular mechanisms of protein structure and function. The Open Force Field (OpenFF) Initiative develops open, reproducible force fields for atomistic simulations, delivering automated infrastructure and systematic methodology for force field fitting and validation as well as version-controlled force field releases. OpenFF force fields assign parameters using direct chemical perception via the SMIRKS cheminformatics language, providing coverage of a large chemical space with fewer parameters than conventional atom-typed force fields. The most recent force field release, Sage (OpenFF 2.0.0), provides valence parameters trained against quantum chemical (QC) data and Lennard-Jones parameters trained against condensed phase properties of pure liquids and binary mixtures. Sage achieves competitive accuracy on benchmarks of the energies and geometries of QC minima, solvation free energies, and protein-ligand binding free energies. Here we describe the extension of Sage to proteins, resulting in a self-consistent force field that can simulate canonical and covalently modified proteins and small molecules. We used protein-specific SMIRKS to train proper torsions to two-dimensional QC scans of the backbone and sidechain dihedrals of capped peptides. The parameters were validated using benchmarks of published NMR observables for small peptides, folded proteins, and disordered proteins. Beyond force field parameters, the OpenFF software infrastructure now supports loading proteins from PDB files, iterating over hierarchies such as residues, and exporting parametrized systems to common molecular dynamics formats.

Gmak: A Parameter-Space Mapping Strategy for Force-Field Calibration.

In the context of classical molecular simulations, the accuracy of a force field is highly influenced by the values of the relevant simulation parameters. In this work, a parameter-space mapping (PSM) workflow is proposed to aid in the calibration of force-field parameters, based mainly on the following features: (i) regular-grid discretization of the search space; (ii) partial sampling of the search-space grid; (iii) training of surrogate models to predict the estimates of the target properties for nonsampled parameter sets; (iv) post hoc interpretation of the results in terms of multiobjective optimization concepts; (v) attenuation of statistical errors achieved via empiric extension of the duration of the simulations; (vi) iterative search-space translation according to a user-defined scalar objective function that measures the accuracy of the force field (e.g., the weighted root-mean-square deviation of the target properties relative to the reference data). This combination of features results in a hybrid of a single- and a multiobjective optimization strategy, allowing for the approximate determination of both a local minimum of the chosen objective function and its neighboring Pareto efficient points. The PSM workflow is implemented in the extensible Python program gmak, which is made available in the Git repository at http://github.com/mssm-labmmol/gmak. Using this implementation, the PSM workflow was tested in a proof-of-concept fashion in the recalibration of the Lennard-Jones parameters of the 3-point Optimal Point Charge (OPC3) water model for compatibility with the GROMOS treatment of nonbonded interactions. The recalibrated model reproduces typical pure-liquid properties with an accuracy similar to the original OPC3 model and represents a significant improvement relative to the Simple Point Charge (SPC) model, which is the official recommendation for simulations using GROMOS force fields.

Predicting the Thermodynamics of Ionic Liquids: What to Expect from PC-SAFT and COSMO-RS?

Two popular thermodynamic modeling frameworks, namely, the PC-SAFT equation of state and the COSMO-RS model, are benchmarked for their performance in predicting the thermodynamic properties of pure ionic liquids (ILs) and the solubility of CO2 in ILs. The ultimate goal is to provide an illustration of what to expect from these frameworks when applied to ILs in a purely predictive way with established parametrization approaches, since the literature generally lacks their mutual comparisons. Two different modeling approaches with respect to the description of the molecular structure of ILs are tested within both models: a cation-anion pair as (i) a single electroneutral supermolecule and (ii) a pair of separately modeled counterions (ion-based approach). In general, we illustrate that special attention should be paid when estimating unknown thermodynamic data of ILs even with these two progressive thermodynamic frameworks. For both PC-SAFT and COSMO-RS, the supermolecule approach generally yields better results for the vapor pressure and the vaporization enthalpy of pure ILs, while the ion-based approach is found to be more suitable for the solubility of CO2. In spite of some shortcomings, COSMO-RS with the supermolecule approach shows the best overall predictive capabilities for the studied properties. The ion-based strategy within both models has significant limitations in the case of the vaporization properties of ILs. In COSMO-RS, these limitations can, to a certain extent, be surpassed by additional quantum mechanical calculations of the ion pairing in the gas phase, while the ion-based PC-SAFT approach still needs a sophisticated improvement to be developed. As an initiating point, we explore one possible and simple route considering a high degree of cross associations between the counterions in the gas phase.

Binary mixtures containing imidazolium ionic liquids: properties measurement

Abstract Densities and transport properties (dynamic viscosity) of pure imidazolium ionic liquids 1-butyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium dicyanamide and their binary mixtures with water and ethanol were measured within the temperature range of 293.15—333.15 K. Obtained experimental data were used to calculate excess molar volume and viscosity deviation. For the chosen binary mixtures, variations of excess molar volume, partial molar volumes of mixture components and of the viscosity deviation with the binary mixture composition were correlated using the Redlich-Kister equation. In addition, variation of viscosity with the binary mixture composition and temperature was fitted using the Jouyban-Acree model.

Effective Debye temperature of ionic liquids and their binary mixtures

Assuming the quasicrystalline structure to ionic liquids the effective Debye temperature of seven pure ionic liquids (H2O, DEAA, DEAS, TEAA, TEAS, TMAA, and TMAS.) has been calculated. Further, the model has been extended to six binary mixtures of (DEAA + H2O, DEAS + H2O, TEAA + H2O, TEAS + H2O, TMAA + H2O, and TMAS + H2O.). This is our first attempt in the study of thermal properties of pure ionic liquids and their binary mixtures. The concept of excess Debye temperature (θDE) has been introduced and correlated with interactions in ionic liquid systems. The input data desired are density, sound speed, heat capacity and ratio of heat capacities (CP/CV).

Volumetric, acoustic and IR spectroscopic properties of binary mixtures (1,2-diaminopropane + methyl-, ethyl-, n-propyl- and n-butyl acetates: A combined experimental and first-principles investigation

Studies of density and speed of sound are commonly used tools to ascertain the properties of pure liquids and the nature of interactions between component molecules of a binary mixture. Herein, the density (ρ) and speed of sound (u) of methyl acetate (MAc), ethyl acetate (EAc), n-propyl acetate (n-PAc) and n-butyl acetate (n-BAc) and their binary mixture with 1,2-diaminopropane (1,2-DAP) were measured over the entire composition range at atmospheric pressure 0.1 MPa and in the temperature range of 298.15–318.15 K with a step of 5 K. Different excess thermo-physical properties including the excess molar volume (VmE), excess ultrasonic speed (uE), excess free volume (VfE), excess intermolecular free length (LfE), and excess molar isentropic compressibility were evaluated from the measured results of ρ and u. The evaluated properties were also analysed in terms of the extent and nature of interactions. The Redlich-Kister polynomial equation was used to correlate the various excess properties to the composition. Further, the u data is analysed by various correlations, Schaaff’s collision factor theory (CFT) and Jacobson’s free length theory (JFLT). The effect of chain length, branching and temperature on the intermolecular interactions and the magnitude of the measured properties have also been systematically analysed. Furthermore, excess molar properties and the intermolecular interactions have been interpreted in the light of Fourier transform infrared spectroscopy (FT-IR) and density functional theory (DFT) studies. Hydrogen-bonded interactions are predicted to play important role in stabilising the binary mixtures.

An electrostatic-variable coarse-grained model for predicting enthalpy of vaporization, surface tension, diffusivity, conductivity, and dielectric constant of aqueous ionic liquid

Electrostatics polarization effects are crucial in predicting various physical properties of pure or aqueous ionic liquids, which have potential applications as green solvents in many fields, such as chemical synthesis and gas separations. Here, we proposed an electrostatic-variable coarse-grained (VaCG) model to predict physical properties of water/[BMIM]+[BF4]- binary mixtures and pure [BMIM]+[SCN]- by introducing a concentration or environment-dependent dielectric constant of ionic liquid, εIL(x), and water, εw(x), in the non-bonded electrostatic interaction term, respectively. The electrostatic polarization induced charge transfer between cation and anion pair of ionic liquid was treated by setting the fragment charges of the three coarse-grained beads, i.e., butyl and methylimidazolium units of [BMIM]+ and anions ([BF4]-or [SCN]-), from the linear scaling generalized energy-based fragmentation electronic structure calculations of clusters with up to 30 cation–anion pairs. This model handles the polarization effect over the range of water mole fraction x = 0 ∼ 100 mol% with the explicit partial charges and implicit treatment of the long-ranged continuum medium without increasing the computational cost. The VaCG model has good performance in predicting thermodynamics (density, enthalpy of vaporization, surface tension), dynamic properties (diffusivity, ionic conductivity), and dielectric properties of aqueous solutions. This model is expected to be applicable to many other complicated systems with significant polarization effects.

Using Computationally-Determined Properties for Machine Learning Prediction of Self-Diffusion Coefficients in Pure Liquids.

The ability to predict transport properties of liquids quickly and accurately will greatly improve our understanding of fluid properties both in bulk and complex mixtures, as well as in confined environments. Such information could then be used in the design of materials and processes for applications ranging from energy production and storage to manufacturing processes. As a first step, we consider the use of machine learning (ML) methods to predict the diffusion properties of pure liquids. Recent results have shown that Artificial Neural Networks (ANNs) can effectively predict the diffusion of pure compounds based on the use of experimental properties as the model inputs. In the current study, a similar ANN approach is applied to modeling diffusion of pure liquids using fluid properties obtained exclusively from molecular simulations. A diverse set of 102 pure liquids is considered, ranging from small polar molecules (e.g., water) to large nonpolar molecules (e.g., octane). Self-diffusion coefficients were obtained from classical molecular dynamics (MD) simulations. Since nearly all the molecules are organic compounds, a general set of force field parameters for organic molecules was used. The MD methods are validated by comparing physical and thermodynamic properties with experiment. Computational input features for the ANN include physical properties obtained from the MD simulations as well as molecular properties from quantum calculations of individual molecules. Fluid properties describing the local liquid structure were obtained from center of mass radial distribution functions (COM-RDFs). Feature sensitivity analysis revealed that isothermal compressibility, heat of vaporization, and the thermal expansion coefficient were the most impactful properties used as input for the ANN model to predict the MD simulated self-diffusion coefficients. The MD-based ANN successfully predicts the MD self-diffusion coefficients with only a subset (2 to 3) of the available computationally determined input features required. A separate ANN model was developed using literature experimental self-diffusion coefficients as model targets. Although this second ML model was not as successful due to a limited number of data points, a good correlation is still observed between experimental and ML predicted self-diffusion coefficients.

DETERMINATION OF THE NONLINEAR PARAMETER AND INTERNAL PRESSURE IN A LIQUID BY THE ACOUSTIC METHOD

An acoustic method is proposed for assessing the molecular properties of a liquid, determining the nonlinear parameter of liquids from the ratio of the first and second harmonics when the acoustic wave changes, and using this parameter to measure the internal pressure. In addition, the proposed method measures intermolecular distances for the studied liquids. In organ fluids, the effects of sound scattering and wave interaction are enhanced. In body fluids, at the molecular level, there is a small amount of microscopic bubbles. This leads to the appearance of the phenomenon of cavitation. These phenomena can be harmful, but not always. There are devices for biological and pharmaceutical technologies, medical devices that successfully use these effects. The paper presents a functional diagram of the experiment, identifies the oscillograms of acoustic signals of finite amplitude at different distances from the emitter. The same devices based on quartz plates 25 mm in diameter with a resonance frequency of 3 MHz were used as the emitter and receiver. This difference of approximately three times the resonance frequencies of the sensors and the acoustic signal ensures the linearity of the amplitude-frequency response of both sensors. Nonlinear acoustic methods are a global trend in biomedical research, as they open up new opportunities and prospects in the development of medical devices. The appearance of higher harmonics in the curvature of the initial harmonic wave of finite amplitude can be used for express analysis of the physical properties of pure liquids and especially aqueous solutions of organic substances. This method of experimental determination of the nonlinear parameter and internal pressure in a liquid is more convenient than the static one, since it does not require the use of high excess static pressures. The proposed acoustic method gives less error than the dynamic one. The accuracy of such a determination can be sufficient to judge the change in the intermolecular interaction in liquids.

Systematic optimization of a fragment-based force field against experimental pure-liquid properties considering large compound families: application to oxygen and nitrogen compounds.

The CombiFF approach is a workflow for the automated refinement of force-field parameters against experimental condensed-phase data, considering entire classes of organic molecules constructed using a fragment library via combinatorial isomer enumeration. One peculiarity of this approach is that it relies on an electronegativity-equalization scheme to account for induction effects within molecules, with values of the atomic hardness and electronegativity as electrostatic parameters, rather than the partial charges themselves. In a previous article [M. P. Oliveira, M. Andrey, S. R. Rieder, L. Kern, D. F. Hahn, S. Riniker, B. A. C. Horta and P. H. Hünenberger, J. Chem. Theory. Comput. 2020, 16, 7525], CombiFF was introduced and applied to calibrate a GROMOS-compatible united-atom force field for the saturated acyclic (halo-)alkane family. Here, this scheme is employed for the construction of a corresponding force field for saturated acyclic compounds encompassing eight common chemical functional groups involving oxygen and/or nitrogen atoms, namely: ether, aldehyde, ketone, ester, alcohol, carboxylic acid, amine, and amide. Monofunctional as well as homo-polyfunctional compounds are considered. A total of 1712 experimental liquid densities ρliq and vaporization enthalpies ΔHvap concerning 1175 molecules are used for the calibration (339 molecules) and validation (836 molecules) of the 102 non-bonded interaction parameters of the force field. Using initial parameter values based on the GROMOS 2016H66 parameter set, convergence is reached after five iterations. Given access to one processor per simulated system, this operation only requires a few days of wall-clock computing time. After optimization, the root-mean-square deviations from experiment are 29.9 (22.4) kg m−3 for ρliq and 4.1 (5.5) kJ mol−1 for ΔHvap for the calibration (validation) set. Thus, a very good level of agreement with experiment is achieved in terms of these two properties, although the errors are inhomogeneously distributed across the different chemical functional groups.

Systematic Optimization of a Fragment-Based Force Field against Experimental Pure-Liquid Properties Considering Large Compound Families: Application to Saturated Haloalkanes.

Direct optimization against experimental condensed-phase properties concerning small organic molecules still represents the most reliable way to calibrate the empirical parameters of a force field. However, compared to a corresponding calibration against quantum-mechanical (QM) calculations concerning isolated molecules, this approach is typically very tedious and time-consuming. The present article describes an integrated scheme for the automated refinement of force-field parameters against experimental condensed-phase data, considering entire classes of organic molecules constructed using a fragment library via combinatorial isomer enumeration. The main steps of the scheme, referred to as CombiFF, are as follows: (i) definition of a molecule family; (ii) combinatorial enumeration of all isomers; (iii) query for experimental data; (iv) automatic construction of the molecular topologies by fragment assembly; and (v) iterative refinement of the force-field parameters considering the entire family. As a first application, CombiFF is used here to design a GROMOS-compatible united-atom force field for the saturated acyclic haloalkane family. This force field relies on an electronegativity-equalization scheme for the atomic partial charges and involves no specific terms for σ-holes and halogen bonding. A total of 749 experimental liquid densities ρliq and vaporization enthalpies ΔHvap concerning 486 haloalkanes are considered for calibration and validation. The resulting root-mean-square deviations from experiment are 49.8 (27.6) kg·m-3 for ρliq and 2.7 (1.8) kJ·mol-1 for ΔHvap for the calibration (validation) set. The values are lower for the validation set which contains larger molecules (stronger influence of purely aliphatic interactions). The trends in the optimized parameters along the halogen series and across the compound family are in line with chemical intuition based on considerations related to size, polarizability, softness, electronegativity, induction, and hyperconjugation. This observation is particularly remarkable considering that the force-field calibration did not involve any QM calculation. Once the time-consuming task of target-data selection/curation has been performed, the optimization of a force field only takes a few days. As a result, CombiFF enables an easy assessment of the consequences of functional-form decisions on the accuracy of a force field at an optimal level of parametrization.

A Polarization-Consistent Model for Alcohols to Predict Solvation Free Energies.

Classical nonpolarizable models, normally based on a combination of Lennard-Jones sites and point charges, are extensively used to model thermodynamic properties of fluids, including solvation. An important shortcoming of these models is that they do not explicitly account for polarization effects, i.e., a description of how the electron density responds to changes in the molecular environment. Instead, polarization is implicitly included, in a mean-field sense, into the parameters of the model, usually by fitting to pure liquid properties (e.g., density). This causes problems when trying to describe thermodynamic properties that involve a change of phase (e.g., enthalpy of vaporization), that directly depend on the electronic response of the medium (e.g., dielectric constant), and that require mixing or solvation in different media (e.g., solvation free energies). Fully polarizable models present a natural route for addressing these limitations but at the price of a much higher computational cost. In this work, we combine the best of those two approaches by running fast simulations using nonpolarizable models and applying post facto corrections to the computed properties in order to account for the effects of polarization. By applying this new paradigm, a new united-atom force field for alcohols is developed that is able to predict both pure liquid properties, including dielectric constant, and solvation free energies in different solvents with a high degree of accuracy. This paves the way for the development of a generic classical nonpolarizable force field that can predict solvation of drug-like molecules in a variety of solvents.

Parametrization and Molecular Dynamics Simulations of Nitrogen Oxyanions and Oxyacids for Applications in Atmospheric and Biomolecular Sciences.

Nitrogen oxyanions and oxyacids are important agents in atmospheric chemistry and medical biology. Although their chemical behavior in solution is relatively well understood, they may behave very differently at the water/air interface of atmospheric aerosols or at the membrane/water interface of cells. Here, we developed a fully classical model for molecular dynamics simulations of NO3-, NO2-, HNO3, and HNO2 in the framework of the GROMOS 53A6 and 54A7 force field versions. The model successfully accounted for the poorly structured solvation shell and ion pairing tendency of NO3-. Accurate pure-liquid properties and hydration free energies were obtained for the oxyacids. Simulations at the water/air interface showed a local enrichment of HNO3 and depletion of NO3-. The effect was discussed in light of earlier spectroscopic data and ab initio calculations, suggesting that HNO3 behaves as a weaker acid at the surface of water. Our model will hopefully allow for efficient and accurate simulations of nitrogen oxyanions and oxyacids in solution and at microheterogeneous interface environments.

Development of Coarse-Grained Force Field by Combining Multilinear Interpolation Technique and Simplex Algorithm.

A fast, reasonable, and transferable coarse-grained (CG) molecular dynamics force field (FF) is essential to combine experimental and simulation data. However, the parameterization of CG FF usually requires massive computation, which hinders its rapid development. Here, we presented an efficient optimization protocol by combining multilinear interpolation technique with simplex algorithm. In this preliminary work, taking the experimental properties as the benchmark, we constructed a new set of CG FF for water and n-alkanes by adopting piecewise Morse function to describe the nonbonded interactions. This CG FF has a delicate balance between efficiency, accuracy, and transferability and well reproduced the correct structural and thermodynamics properties of pure water and alkane liquids. More importantly, optimized Morse potential was also successfully applied to describe the interactions between water and n-alkanes. It nicely predicted the phase separation, interface tension, hydration free energy, and formation of microemulsions of water/oil mixtures. © 2019 Wiley Periodicals, Inc.

Corrigendum to “Density and isothermal compressibility of ionic liquids from perturbed hard -sphere chain equation of state” [J. Mol. Liq. 174 (2012) 52–57

Abstract After a careful reconsideration of the article (S. M. Hosseini, M. M. Papari, J. Moghadasi, Journal of Molecular Liquids, 174 (2012) 52–57), several typos are appearing in some of the key equations of this article which would not allow the readers to utilize the underlying equation of state for the calculation of volumetric properties of pure ionic liquids without any problem. Regarding this, Erratum is presented to fix this issue.

Rheology of Pure Ionic Liquids and Their Complex Fluids: A Review

Ionic liquids (ILs) are liquid salts at ambient or lower temperatures and consist of ions and short-lived ion pairs. They are potential alternatives to toxic, hazardous, highly flammable, and volatile solvents for preparing solutions, dispersions, gels, composites, and polymeric melts. ILs have some very interesting and unique characteristics like good chemical and thermal stability and very low vapor pressures. They have good solvation interactions with a wide range of organic, inorganic, and polymeric compounds. They can enhance colloidal stability and the elasticity range of polymers. ILs are environmental friendly, easily recyclable, and structurally similar to the conventional solvents. For optimal performance, it is necessary to fully understand the rheological properties of ILs and their different systems for academic interests such as understanding the ability of ILs as processing AIDS particularly in film casting, fiber spinning and spraying, comprehension of thermodynamics and dynamics of polymer chains in ILs, analyzing the hydrodynamic volume of dispersed polymer, polymer-ILs interactions, characterizing the viscoelastic properties and nanophase-ILs interactions in nanocomposite systems, analyzing the plasticization efficiency, and the final properties of the composite system. The rheological analysis is also important for industrial purposes particularly for designing processing techniques and suitable operating conditions for IL based systems. The aim of this review is to give an overview of the rheological properties of pure ionic liquids and solutions, dispersions, gels, composites, and melts based on ionic liquids.