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

Abstract

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.

Is density enough to predict the rheology of natural sediments?

“…Mud samples having higher organic matter content (RVand RT) had a higher complex modulus (417 Pa and 7909 Pa) than the ones with lower organic matter content (13 Pa and 1774 Pa), for a given density. The complex modulus is a measure of the consistency of the system, while the phase angle is representative of the degree of structuration (Lupi et al 2016;Shakeel et al 2018;Shakeel et al 2019b;Shakeel et al 2019c). The results showed that the consistency of the mud samples can be varied by changing the OM content or density, whereas the degree of structuration remains the same for all the samples.…”

Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration

“…Note that the high viscosity of cellulose-IL solution adversely affects heat-and mass transfer; the problem is compounded if the solution shows Newtonian behavior, i.e., no shear-thinning is produced by increasing solution shear (agitation) [29]. Consequently, studying rheological properties such as viscoelasticity and flow behavior of cellulose solutions is important [30,31]. These properties are relevant because they allow process optimization, or reveal functional properties for A recent publication showed that cellulose thermal stability in BuMeImCl (24 h at 130 • C) is enhanced by co-solubilization of several amino acids, L-arginine being the most effective stabilizer.…”

Interfacial and Bulk Stabilization of Oil/Water System: A Novel Synergistic Approach

“…The micrograph of the prepared system shows the existence of a structured network along with the nanoparticle-stabilized droplets (Figure 1c), which verified the dual stabilization of the system. Apart from microscopic analysis, rheological investigation was also carried out for the prepared systems, which is a useful tool to analyse the structure-property relationship in different systems [19]. Frequency sweep tests were performed, within the linear viscoelastic regime, for the samples to investigate their mechanical properties without disturbing the structure.…”