Deep eutectic solvents, as a new type of eco‐friendly solvent, have attracted increasing attention in chemistry for the extraction and separation of target compounds from various samples. To ...summarize the application of deep eutectic solvents, this review highlights some of the unique properties of deep eutectic solvents and deep‐eutectic‐solvent‐based materials, as well as their applications in extraction and separation. In this paper, the available data and references in this field are reviewed to summarize the application developments of deep eutectic solvents. Based on the development of deep eutectic solvents, the exploitation of new deep eutectic solvents and deep‐eutectic‐solvent‐based materials are expected to diversify into extraction and separation.
Solvents generally in liquid form, are used to dissolve, dilute, suspend any substances or extract other materials. More than one-third of the drugs listed in the various Pharmacopeias fall into the ...poorly water-soluble or water-insoluble categories. For more than 200 years, traditional solvents could be used as a solvent for substances that were insoluble in water. But the usage of these types of solvents should be decreased because these types of solvents are volatile, flammable, and often toxic. Also, the industrialist’s usages in different types of processes prove the risk for workers. In recent years, several solvents have been proposed to be the greener replacement for traditional solvents. Replacing hazardous chemicals with more environmentally friendly alternatives is a matter of current interest, in line with the philosophy of Green Chemistry. The use of nontraditional or nonconventional solvents such as supercritical fluids (SCFs) such as Carbon dioxide (CO2) and water, fluorous solvents, solventless reaction Ionic liquids (ILs) and their derivatives polymeric ILs and magnetic ILs, and deep eutectic solvents (DESs) are alternatives for environmentally unfriendly traditional solvents. Among them, DES is a neoteric class of green solvents defined as a mixture of two or more compounds that are typically solid at room temperature, but when combined at a particular molar ratio, changes into a liquid at room temperature. It is assumed that eutectic mixtures show low volatility, have a broad liquid range, and are water-compatible, non-flammable, non-toxic, biocompatible, and eco-friendly. Eutectic solvents have been useful in several pharmaceutical fields, such as the increase of drug solubility, permeation, and absorption.
Deep eutectic solvents have emerged in green chemistry only seventeen years ago and yet resulted in a plethora of publications covering various research areas and diverse fields of application. Deep ...eutectic solvents appear as promising alternatives to conventional organic solvents due to their straightforward preparation using highly accessible and natural compounds. They display also high tunability. Here we present the classification and preparation methods of deep eutectic solvents. We detail their physicochemical properties such as phase behavior, density, viscosity, ionic conductivity, surface tension, and polarity. Properties are controlled by the choice of the forming compounds, molar ratio, temperature, and water content.
Binary mixtures of liquid metal (LM) or low‐melting‐point alloy (LMPA) in an elastomeric or fluidic carrier medium can exhibit unique combinations of electrical, thermal, and mechanical properties. ...This emerging class of soft multifunctional composites have potential applications in wearable computing, bio‐inspired robotics, and shape‐programmable architectures. The dispersion phase can range from dilute droplets to connected networks that support electrical conductivity. In contrast to deterministically patterned LM microfluidics, LMPA‐ and LM‐embedded elastomer (LMEE) composites are statistically homogenous and exhibit effective bulk properties. Eutectic Ga‐In (EGaIn) and Ga‐In‐Sn (Galinstan) alloys are typically used due to their high conductivity, low viscosity, negligible nontoxicity, and ability to wet to nonmetallic materials. Because they are liquid‐phase, these alloys can alter the electrical and thermal properties of the composite while preserving the mechanics of the surrounding medium. For composites with LMPA inclusions (e.g., Field's metal, Pb‐based solder), mechanical rigidity can be actively tuned with external heating or electrical activation. This progress report, reviews recent experimental and theoretical studies of this emerging class of soft material architectures and identifies current technical challenges and opportunities for further advancement.
Elastomers embedded with liquid metal and low‐melting‐point alloy inclusions exhibit a unique combination of electrical, thermal, and mechanical properties. These gel‐like systems represent an emerging class of soft multifunctional composites that have potential applications in wearable computing, bioinspired robotics, and shape‐programmable architectures. Recent efforts in this domain are reviewed and opportunities for further advancement are identified.
Al–Cu–Si ternary eutectic alloys with a bimodal eutectic structure exhibit a good combination of strength and plasticity owing to the multiscale hierarchical microstructure. Previous studies have ...reported that bimodal eutectic structures can be successfully prepared by rapid solidification at a cooling rate of greater than 102 °C/s. In the present study, a bimodal eutectic structure was successfully prepared at a cooling rate of less than 10 °C/s by adding a small amount of Sr to Al–Cu–Si ternary eutectic alloys. Additions of Sr led to a notable modification of the microstructure from a mixed eutectic structure to a bimodal eutectic structure. Samples with the bimodal eutectic structure showed greater hardness, strength, and elongation than samples with mixed eutectic structure. In particular, the elongation increased significantly from 6% to 28%. The additions of Sr changed the microstructure of the Al–Si phase from needles to globular shapes, which are finely dispersed all through the microstructure. These results indicate that the improved mechanical properties with the addition of Sr can mainly be attributed to the development of a multiscale hierarchical microstructure with fine eutectic cells.
Eutectic Al-Ni alloys are widely faced as materials to be considered for advanced structural components. Nevertheless, still there is a lack of research on microstructural aspects of the eutectic ...Al-6.3 wt%Ni alloy and important points need to be addressed, such as, the morphology of the unsteady solidified eutectic, size and distribution of phases under different solidification cooling rates and the effects of the resulting microstructural features on mechanical properties. As such, in the present study, an Al-6.3 wt%Ni alloy is directionally solidified under a wide range of cooling rates and the resulting microstructure is shown to be formed by eutectic colonies. Three general microstructural features characterize the colony: a fine central zone composed of fibrous α-Al + Al3Ni eutectic, a boundary coarse zone formed by lamellar eutectic, and an Al-rich zone delimiting the colony. A quantitative analysis relating solidification thermal parameters to Al3Ni and colony spacings is outlined. Furthermore, the evolution of tensile properties as a function of these spacings was examined, and the highest strength and elongation of 160 MPa and 15%, respectively, are associated with an ultrafine bimodal structure formed by eutectic colonies with 55 μm in spacing containing very fine fibers (300 nm in spacing) and lamellae with 750 nm in spacing.
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•Eutectic colonies typify the microstructure of directionally solidified Al-6.3 wt%Ni alloy.•The colony has a bimodal structure: fine Al3Ni fibers (center)/coarse lamellae (boundary).•Growth laws: colony/inter-fiber/lamellar spacings vs. growth/cooling rates are proposed.•Experimental equations relating tensile properties vs. colony spacing are proposed.
AlxCrFeNi eutectic multi-component alloys were prepared to obtain excellent mechanical properties by double-phase strengthening. The X-ray diffraction results showed that the crystal structure were ...both body-centered cubic and energy-dispersive X-ray spectrometer identified that the two phases are ordered NiAl intermetallic and disordered Fe, Cr solid solution. The formation of eutectic structures was introduced by a simplified dynamic model. After mechanical tests, the alloys presented excellent compressive strength and unexpected large deformation. Due to the solid solution and fine-grain strengthening resulted by Al addition, mechanical properties of AlxCrFeNi alloys exhibited regularity in some degree. Among all alloys, Al1.3CrFeNi has the highest fracture strength and Al0.9CrFeNi has the most excellent strain. Besides, Al1.2CrFeNi alloy showed a good combination of strength and ductility.
In last years, a plethora of extraction techniques has emerged as environmental-friendly alternatives to conventional extraction procedures. In this particular field, a novel class of solvents known ...as deep eutectic solvents (DES) has arisen as a new and very promising tool. Compared with conventional organic solvents, DES as well as the so-called natural deep eutectic solvents (NADES) have attracted considerable attention due to the fact that they not only are eco-friendly, non-toxic, and biodegradable organic compounds but also have a low cost, being easy to produce in the own laboratory. The present review provides a critical and organized overview of novel extraction techniques using DES as extracting solvents that were applied in food, biological and environmental sample analysis. An evaluation of how these DES/NADES could improve extraction yields of a variety of analytes and advantages and limitations of each proposal will be discussed and compared with earlier studies.
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•DES and NADES are environmentally-friendly alternative to organic solvents.•Novel applications of DES/NADES in microextraction techniques.•Recent microextraction techniques based in DES/NADES are compared with earlier approaches.•Future perspectives of DES/NADES in microextraction techniques are stated.
Zinc‐ion batteries (ZIB) present great potential in energy storage due to low cost and high safety. However, the poor stability, dendrite growth, and narrow electrochemical window limit their ...practical application. Herein, we develop a new eutectic electrolyte consisting of ethylene glycol (EG) and ZnCl2 for dendrite‐free and long‐lifespan ZIBs. The EG molecules participate in the Zn2+ solvation via coordination and hydrogen‐bond interactions. Optimizing the ZnCl2/EG molar ratio (1 : 4) can strengthen intermolecular interactions to form ZnCl(EG)+ and ZnCl(EG)2+ cations. The dissociation–reduction of these complex cations enables the formation of a Cl‐rich organic–inorganic hybrid solid electrolyte interphase film on a Zn anode, realizing highly reversible Zn plating/stripping with long‐term stability of ≈3200 h. Furthermore, the polyaniline||Zn cell manifests decent cycling performance with ≈78 % capacity retention after 10 000 cycles, and the assembled pouch cell demonstrates high safety and stable capacity. This work opens an avenue for developing eutectic electrolytes for high‐safety and practical ZIBs.
A brand new eutectic electrolyte consisting of ethylene glycol (EG) and ZnCl2 has a unique solvation structure and could enable the formation of a Cl‐rich organic–inorganic hybrid solid electrolyte interphase film on a Zn anode, realizing highly reversible Zn plating/stripping.
A stricter definition of a deep eutectic solvent (DES) is urgent, so that it may become a sound basis for further developments in this field. This communication aims at contributing to deepening the ...understanding of eutectic and deep eutectic mixtures concerning their definition, thermodynamic nature and modelling. The glut of literature on DES applications should be followed by a similar effort to address the fundamental questions on their nature. This hopefully would contribute to correct some widespread misconceptions, and help to establish a stringent definition of what a DES is. DES are eutectic mixtures for which the eutectic point temperature should be lower to that of an ideal liquid mixture. To identify and characterize them, their phase diagrams should be known, in order to compare the real temperature depression to that predicted if ideality is assumed, and to define composition ranges for which they are in the liquid state at operating temperatures. It is also shown that hydrogen bonding between the DES components should not be used to define or characterize a DES, since this would describe many ideal mixtures. The future of deep eutectic solvents is quite promising, and we expect that this work will contribute to the efficient design and selection of the best DES for a given application, and to model properties and phase equilibria without which the process design is impractical.
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