Chloride Deep Eutectic Solvent Research Articles

Tough and highly conductive deep eutectic solvent-based gel electrolyte strengthened by high aspect ratio of hemp lignocellulosic nanofiber

Flexible electronic sensing and energy storage technology impose heightened demands on the mechanical and stable properties of gel electrolyte materials. Lignocellulosic nanofiber (LCNF) present a promising avenue for improving the properties of electrolyte networks and mechanical strength. In this study, LCNF derived from hemp fibers was prepared using lactic acid/choline chloride deep eutectic solvent (DES) through a combination of cooking and colloid mill mechanical treatment to achieve nanocellulose with a high aspect ratio and uniform dimensions. The outcomes demonstrated that LCNF, a width of below 20 nm and a length of over 5 μm, can be effectively produced through the DES cooking pretreatment in conjunction with colloid mill mechanical treatment. Meanwhile, DES lignin possessed a purity of ~90 % and was obtained as a by-product. Subsequently, the as-prepared LCNF was integrated as a nanofiller into gel electrolyte. Ag-L NPs/LCNF/DES/PAA exhibited dense porous structures and showcased exceptional properties, including a high conductivity exceeding 10 mS/cm and remarkable adhesion strength surpassing 100 KPa. The presence of LCNF allowed Ag-L NPs/LCNF/DES/PAA to achieve strains above 1000 % and compression properties over 1000 KPa. The supercapacitor based on this assembly had a high specific capacitance of 271 F g−1 at 0.5 A g−1), along with an impressive capacity retention rate reaching ~100 % after 3000 cycles. This investigation offers valuable insights into the utilization of lignocellulosic multi-component approaches in the development of flexible electronic devices.

The influence of chirality on the structure of a tartaric acid-choline chloride deep eutectic solvent

The wide range of properties, relative ease and low cost of using Deep Eutectic Solvents garners them interest in an ever expanding range of applications. Among common DES components many are naturally occurring chiral molecules. Here we present the liquid structure of either single enantiomeric or racemic tartaric acid with choline chloride at a molar ratio of 2 choline chloride to 1 tartaric acid, as well as the influence of low amounts of added water (2:1:2) from neutron scattering data with H/D isotropic substitution, refined using empirical potential structure refinement. We show that the overall structure remains the same between the different enatiomeric compositions, with small differences in interactions only occurring between the tartaric acid molecules. The overall structure is also robust towards hydration, similar to what has been found in other DES. We also compare our structures to the structures of DES comprising of similar carboxylic acids (1:1 choline chloride - malic acid, 1:1 choline chloride - oxalic acid), finding overall similar dominant interactions, with differences that may be attributable to the number of available hydrogen bonding sites and steric effects.

Development of a new continuous homogenous liquid phase microextraction procedure based on in-situ preparation of deep eutectic solvent; application in the analysis of aliphatic amines in urine samples by GC–MS

In the present work, a new microextraction procedure combined with gas chromatography-mass spectrometry has been developed for the analysis of several aliphatic amines from urine sample. The sample preparation method was a continuous homogenous liquid phase microextraction that was based on in-situ preparation of 4-chlorophenol: choline chloride deep eutectic solvent. The deep eutectic solvent was prepared by passing the mixture of related compounds through a syringe barrel filled with exothermic salts (calcium chloride and potassium bromide). The released heat by dissolving the salts and increasing the solution ionic strength assists the formation of the deep eutectic solvent. The influence of various factors on the efficiency of the proposed procedure including salts amount, flow rate, pH, salting-out effect, and extraction solvent volume was studied. The calibration curves were linear broadly over the concentration range of 1.2–250 ng mL−1 with coefficient of determinations ≥0.996. The enrichment factors were in the range of 188–246 and the limits of detection and quantification were 0.16–0.37 and 0.56–1.2 ng mL−1, respectively. Based on the results, the offered method was sensitive, rapid, eco-friendly, and efficient for extracting and determining aliphatic amines in urine samples.

Choline chloride-based deep eutectic solvents (NADES): Potential use as green extraction media for polyphenols from Mentha pulegium, antioxidant activity, and antifungal activity

With the introduction of the concept of green chemistry, eco-friendly extraction processes are moving from an option to a must. Combined with ultrasound-assisted extraction (UAE), 9 choline chloride deep eutectic solvents were screened for the extraction of antioxidant polyphenolic compounds from Mentha pulegium (Lamiaceae). Data indicated that among the 9 types of choline chloride-based solvents tested, Choline Chloride: Lactic acid (1:2) and Choline Chloride: Glycerol (1:2) were selected as the most promising solvent compared to 80 % methanol. The extraction conditions were statistically investigated using Response surface methodology conducted by Boc-Behnken design (BBD). The optimal operational conditions were: temperature of extraction 80 °C, extraction time of 30 and 51 min with 44 and 20 % water content in Choline Chloride: Glycerol (1:2) and Choline Chloride: Lactic acid (1:2), respectively. The selected NADES extracts recorded excellent scavenging activity at a concentration of 1,9 mg/ml higher than 93 %. HPLC–MS/MS analysis revealed that Phenolic acids mainly hydroxycinnamic acids, such as rosmarinic acid, chlorogenic acid, salvianolic acid, caffeoyl glucose, lithospermic acid, and its derivatives, dominated the extracts tested. Otherwise, our results support that the proposed eutectic solvents are able to provide a higher selectivity toward flavonoids such as apigenin derivative, kaempferol coumaroyl hexoside, epi gallocatechin and quercetin o glucopyranoside gallate. The antifungal activity of the optimized extracts revealed inhibition of over than 88 % against the postharvest citrus fungal: Phytophthora citrophthora. In light of the presented results and considering the nature of components constituting Natural deep eutectic solvents (NADES), make these green, novel, sustainable, and low-cost extracts fresh samples for further investigation.

Solvent-Free Synthesis of α-Cyanophosphonates from β-Nitro­styrenes by Using a Deep-Eutectic Solvent Catalyst

Abstractα-Cyanophosphonates, which are useful reagents for the Horner–Wittig reaction, were synthesized under solvent-free conditions by using a choline chloride–zinc chloride deep-eutectic solvent (DES) as a catalyst. This is only the second report on the synthesis of these compounds. In the previous report, diethyl trimethylsilyl phosphite was used as a reagent and TiCl4 as a catalyst, whereas in this study, both the reagent (triphenylphosphine) and the catalyst (choline chloride–zinc chloride DES) are cheaper, more readily available, and less harmful than those used in the previous work. Moreover, the process involves an interesting cascade reaction between a β-nitrostyrene and two equivalents of triphenyl phosphite, leading to the desired product by a new synthetic route. The products can be used in the pharmaceutical and agricultural industries, in addition to their synthetic applications in the preparation of α,β-unsaturated nitriles. The reactions were completed on using 20 mol% of DES at 80 °C in six hours. Ten different β-nitrostyrenes were synthesized in yields of 55–87% after purification. β-Nitrostyrenes containing electron-donating groups showed higher yields. The reaction failed when aliphatic or heteroaromatic nitroalkenes or β-nitrostyrenes with electron-withdrawing substituents were employed. Finally, three plausible mechanistic routes are proposed for the reaction, starting with the nucleophilic addition of triphenyl phosphite to the carbon, nitrogen, or oxygen atom in the α-position.

Continuous liquid–liquid extraction to recover lignin and furanics from lactic acid: Choline chloride deep eutectic solvent after cooking of spruce

Lactic acid: choline chloride mixed in a 10:1 ratio is known to be a suitable delignification solvent. This deep eutectic solvent (DES) can produce lignin and hemicellulose derivatives as byproducts to cellulose. Hemicellulose byproducts include furanic compounds like furfural and 5-HMF. Sustainable and economically viable fractionation of lignin and furanics from the DES is required. After removing the larger lignin (>2500 Da) through water precipitation, non-precipitated molecules such as smaller lignin molecules and furanics can be retrieved through liquid–liquid extraction (LLX). In a previous investigation on solvent extraction conducted in a batch mode, 2-MTHF and guaiacol have been identified as potential solvents. This study investigates the application of a continuous centrifugal contactor separator (CCCS) and Karr reciprocating plate column for LLX from aqueous DES-black liquor remaining after water-precipitation, was employed as the feed. Single stage CCCS operation exhibited extraction yields close to equilibrium yields, thus almost 100 % extraction efficiency. Performing a two-stage countercurrent LLX process via CCCS showed increased removal for furfural and 5-HMF extraction, while lignin extraction yield remained at about 90 %, comparable to single-stage extraction. Karr column countercurrent extraction with different solvent-to-feed ratios (0.5 and 1) yielded approximately 99 % furfural extraction. For 2-MTHF system, 5-HMF achieved 99 % extraction yield at a solvent-to-feed ratio of 1, while guaiacol yielded around 90 % at both solvent-to-feed ratios. However, 5-HMF extraction using 2-MTHF with a ratio of 0.5 required more stages. For guaiacol improvement of lignin extraction applying more stages was hindered by hydrophobic characteristic of residual lignin in raffinate. Conversely, 2-MTHF's multi-stage approach enhanced smaller lignin extraction influenced by increased lactic acid leaching into solvent. Both CCCS and Karr column methods proved viable for counter-current extraction with both solvents.

Structural and separation evaluation of polysulfone-based loose NF membrane modified with itaconic acid-choline chloride deep eutectic solvent as additive

In this research, a type of deep eutectic solvent (DES) based on itaconic acid-choline chloride (IA-CC) was used as an efficient additive to modify the structure of the polysulfone-based membrane. Structural investigation of the as-obtained loose nanofiltration (LNF) membrane was performed through various analyses. The results showed that the use of a very low amount of IA-CC DES in the structure of the polysulfone (PSF) membrane caused the formation of finger-like pores in the structure and increased the porosity. Consequently, a significant increase in the water flux was obtained compared to the membrane synthesized with polyvinylpyrrolidone (PVP) as a common pore former (from 18.22 to 257.14 LMH). The rejection for anionic and cationic dyes as well as the binary mixtures of dyes was evaluated. The rejection of divalent Mg and Ca ions was 16.5% and 15.0%, respectively, while that of monovalent sodium ions was less than 3%. Based on the best of our knowledge, the highest water flux at low pressure (2 bar) despite the high rejection for dyes among all the NF membranes has been reported in this work. Moreover, the antifouling properties of DES-modified membrane against bovine serum albumin (BSA) showed a slight increase in the antifouling index.

Carboxyl-functionalized graphene oxide/cellulose nanofiber as adsorbents toward methylene blue

An efficient adsorbent for eliminating methylene blue (MB) from water solutions was created by combining carboxyl-functionalized graphene oxide (GO-COOH) with cellulose nanofiber. The GO-COOH was prepared using a malonic acid-choline chloride deep eutectic solvent, resulting in a carboxyl group ratio of 5.3 % and a C/O ratio of 2.15. This novel approach addresses the issue of partial reduction of GO-COOH observed in traditional preparation methods, thereby enhancing the adsorption capacity of the adsorbent for MB (611.44 mg g−1). In general, this method provides the opportunity for producing cellulose-based adsorbents for dye wastewater on a large scale, while being environmentally friendly.

Production of cellooligosaccharides from oil palm bunch in bio-based choline chloride deep eutectic solvents and MALDI-TOF MS analysis of COS mixture

Lignocellulosic biomass pretreatment and cellulose dissolution are principal challenges for its conversion to high-value chemicals, materials and fuels. This work focused on production of soluble cellooligosaccharides (COS) from palm bunch for future use as nutraceutical supplement to enhance human's immune and digestive systems. Deep eutectic solvents (DESs) have been found as eco-friendly, renewable and promising solvents selective for lignin and hemicellulose removal from biomass. Additionally, the investigation of most suitable DES for both cellulose dissolution and subsequently cleavage of cellulose to COS is crucial. In the study, palm empty fruit bunch (EFB) was pretreated in different DES for screening of most favorable cellulose inter- and intra-molecular structural dissolution in a combination with beta,1–4 glycosidic bond cleavage by elevated reaction temperature for COS production. ChCl/urea was found to be the most promising DES for dissolving 76.83% of EFB constituents. The highest COS production yield at 90.1%w/w based on treated EFB fraction (74.7% COS yield based on cellulose in native EFB) was achieved in ChCl/urea DES from cellulose fraction extracted from EFB at 240 °C for 20 min. The study additionally provided insightful characterization and elucidation of COS molecular structure using 2D-HSQC and MALDI-TOF/MS techniques. MALDI-TOF/MS was a promising and rapid technique for simultaneously qualitative and quantitative analysis of COS at different degrees of polymerization in COS product.

Cellulose eutecticgel electrolytes based on ethylene glycol/zinc chloride deep eutectic solvent for flexible solid-state capacitors

In the present work, we successfully prepared a conductive eutecticgel with good mechanical properties, adhesion properties and excellent antifreeze properties by mixing ethylene glycol (EG) as the hydrogen bonding donor and zinc chloride (ZnCl2) as the hydrogen bonding acceptor in different molar ratios to form an anhydrous deep eutectic solvent (DES). Water-soluble cellulose acetate (WSCA), monomer acrylamide (AM), initiator ammonium persulfate (APS) and cross-linking agent MBA (N, N′-methylene bis(acrylamide)) were added into the prepared DES to form a eutecticgel by a simple one-pot cooking strategy. The mechanical properties of the eutecticgel were strengthened by cross-linking of WSCA and PAM chains through hydrogen bonding, and the addition of the DES and ZnCl2 increased the freezing-resistant property of the eutecticgel. The stresses of DES-WSCA/PAM eutecticgel increased with the content of WSCA. The stress of DES-WSCA/PAM eutecticgel gradually becomes larger with the increase of WSCA content, and it can reach 184.07 kPa at 2 % WSCA content. In addition, the capacitor prepared by DES-WSCA/PAM eutecticgel shows excellent performance, with a voltage window of 2 V and a capacitance of 371.5 F/g, which can be operated stably for a long period, and the capacitance can still reach 145.4 F/g even under the condition of −40 °C. Moreover, DES-WSCA/PAM eutecticgel capacitor has a long service life, its capacitance retention rate and coulombic efficiency can reach more than 91 % and 95 %, respectively, after 10,000 times of charging and discharging tests. In summary, DES-WSCA/PAM eutecticgel electrolyte is an ideal material for capacitors, which opens up a new way of thinking for the development of multifunctional cellulose-based eutecticgels with low-temperature resistance, good mechanical properties, and non-irritating for wearable energy storage devices.

Cyclodextrin-based supramolecular deep eutectic solvent (CycloDES): A vehicle for the delivery of poorly soluble drugs

The aim of this work was to develop a new class of deep eutectic solvent (DES) composed of a complexation agent, namely hydroxy-propyl-β-cyclodextrin (HPβCD), to exploit a synergic solubilization-enhancing approach. For this purpose, cyclodextrin-based supramolecular DES (CycloDES) were physical–chemical characterized and loaded with three different BCS class II model drugs, specifically Cannabidiol, Indomethacin, and Dexamethasone, evaluating the influence of different factors on the observed solubility and permeation compared with the only HPβCD/drug complexation.Hence, CycloDESs were presented as a possible vehicle for drugs and represent a novel potential approach for solving BCS class II and IV solubility issues, demonstrating at least a 100-fold improvement in the investigated drug solubilities. Furthermore, CycloDESs demonstrated a significantly improved resistance to dilution preserving a high percentage of drug in solution (i.e. 93% for Indomethacin) when water is added to the DES if compared with a glucose-choline chloride DES, used as a standard. This evidence guarantees the solubility-enhancing effect useful for the delivery of BCS class II and IV drugs converting solid raw material to advantageous liquid vehicles bypassing the rate-determining dissolution step.

DES-based microwave- and ultrasound-assisted extraction of natural products from Rumex hastatus as per response surface methodology

Rumex hastatus D. Don is a medicinal wild herb that abundantly grows in many parts of the world. The current work explores the extraction of its polyphenolic and antioxidant compounds using glycerol-choline chloride deep eutectic solvent and two modern techniques, ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE). The optimization was done as per the response surface methodology. Six responses were studied including total phenolic content (TPC), total flavonoid content (TFC), total condensed tannin content (TCT), ferrous iron-chelating (FIC) activity, DPPH radical scavenging activity (RSA), and ferric reducing antioxidant potential (FRAP). The optimal factors for MAE were 10 s extraction time, 229.40 W power, 40 mL/g SSR (solvent-to-solid ratio) and 60 % DES concentration with the predicted TPC, TFC, TCT, FIC, RSA and FRAP as 64.46 mg GAE/g PM, 155.78 mg RE/g PM, 129.73 mg CE/g PM, 51.46 mg EDTAE/g PM, 235.84 mg AAE/g PM and 129.14 mg AAE/g PM, respectively. For UAE, the predicted optimal factors were 24.30 min sonication time, 47 °C extraction temperature, 40 mL/g SSR and 60 % DES concentration with the predicted TPC, TFC, TCT, FIA, RSA, and FRAP as 56.54 mg GAE/g PM, 148.24 mg RE/g PM, 155.60 mg CE/g PM, 57.83 mg EDTAE/g PM, 240.56 mg AAE/g PM and 111.71 mg AAE/g PM, respectively. Both the models were strongly supported by the validation study with minimal % errors; 2.53–6.38 % for MAE and 1.14–5.30 % for UAE. MAE was more efficient than UAE in terms of time input and recovery of total polyphenols. Therefore, the method based on DES-MAE can safely be recommended for use on an industrial level for obtaining bioactives from R. hastatus.

Comparing DES-mediated ultrasound- and heat-assisted extraction of bioactive metabolites from Saussurea lappa and optimization by RSM and validation studies

Saussurea lappa roots have several important uses in traditional medicine. An efficient and sustainable process is needed to obtain bioactive compounds from them. To address this industrial need, the current project was designed with the objective of developing a green and effective method for the extraction of bioactive metabolites from Saussurea lappa roots. Glycerol-choline chloride DES (deep eutectic solvent) diluted (50 %) with water was used as an extractant and two techniques HAE (heat-assisted extraction) and UAE (ultrasound-assisted extraction) were optimized through 3-factors Box-Behnken designs of RSM (response surface methodology). For each technique, four dependent factors were selected that were total polyphenols (TP, gallic acid equivalents/g (GAE/g)), total flavonoids (TF, rutin equivalents/g (RE/g)), antioxidant capacity (AC, %), and metal chelating capacity (MCC, %). Under the optimized conditions, TP, TF, AC, and MCC in UAE were 7.51 mg GAE/g DM, 4.87 mg RE/g DM, 60.14 % and 62.13 %, respectively, with % error 0.92–4.13, while in HAE, they were 3.48 mg GAE/g DM, 4.40 mg RE/g DM, 51.46 % and 55.61 %, respectively with % error 0.22–4.56. The models were strongly supported by validation experiments. Thus, UAE was more efficient and sustainable than HAE and can, therefore, effectively be used for the extraction of bioactive molecules from S. lappa roots on an industrial scale.

Synthesis of Trimetallic Au/Pd/Ag Hollow Dendrite for Enhancing Electrochemical Sensing Ability Toward Nitrofurans

This study demonstrated a galvanic replacement reaction that synthesized trimetallic Au/Pd/Ag hollow dendrites in a choline chloride deep eutectic solvent. The dendrites' compositions of Au:Pd: Ag ratio can be well controlled by changing the displacement time and the precursor concentration. Their morphologies, chemical compositions, and electronic properties were carefully characterized by TEM, SEM, and XPS techniques. The synthesized dendrites were also employed as modified electrodes for the reduction of nitrofurans. The results show that the trimetallic Au/Pd/Ag hollow dendrites provided better sensing ability than those obtained from bimetallic Pd/Ag and Au/Ag electrodes and monometallic counterparts. This study demonstrated that both the atomic ratio of constituent metal and hollow interior structure strongly affect the catalytic activities of the synthesized Au/Pd/Ag hollow dendrites.

Comparing organic solvents in a combined water precipitation and liquid–liquid extraction process to recover lignin and furanics from a lactic acid: choline chloride deep eutectic solvent used as cooking liquor for cooking of spruce

AbstractExtracting and purifying lignin from wood without compromising cellulose quality is a challenging process. Lactic acid: choline chloride is a deep eutectic solvent (DES) that has been identified as acceptable delignification solvent, producing lignin and hemicellulose as byproducts to the cellulose. Hemicellulose is partly transformed into furanic compounds (such as furfural and 5-HMF). While the larger lignin can be obtained by water precipitation from DES, smaller lignin molecules and furanics can be recovered by liquid–liquid extraction (LLX), either directly or after precipitation of the larger lignin molecules. The presence of water in the DES after water precipitation reduced the mutual miscibility with the solvents, allowing the use of a wider range of solvents in the LLX process. In the precipitation step, all the larger molecular weight lignin (Mw > 5000 Da) can be recovered when adding at least 3.5:1 [g/g] water to DES-black liquor. For the LLX step, guaiacol was found as suitable alternative to the previously published 2-methyltetrahedrofuran (2-MTHF). In addition, here we report the use of 2,2,5,5-Tetramethyl oxolane (TMO), a recent addition to the palette of (potentially) bio-based solvents. The distribution coefficients of smaller lignin molecules and furanics in LLX with guaiacol, TMO and 2-MTHF were compared, revealing that smaller lignin molecules (500–5000 Da) can be recovered with a reasonable distribution coefficient by 2-MTHF and guaiacol. Furfural showed distribution coefficients of at least 1.27 in all three solvents. Guaiacol and TMO both showed a significantly lower lactic acid leaching than 2-MTHF. This makes them potential alternatives for 2-MTHF in this technique. Graphical abstract

Ultrasound‐assisted formic acid–choline chloride deep eutectic solvent pretreatment of cotton straw to extracted lignin

AbstractDeep eutectic solvent (DES) is a new type of green solvent that can be used for the separation of lignocellulosic components. In this study, ultrasound‐assisted DES pretreatment was used to treat cotton straw, which could retain most of the cellulose in cotton straw and separate hemicellulose and lignin at the same time. Here, DESs with different molar ratios were prepared using choline chloride as hydrogen bond acceptor and formic acid as hydrogen bond donor. Simultaneously changing the ultrasonic frequency and DESs synergistic extraction of lignin. Results show that the ultrasonic power is 32 kHz (room temperature), ultrasound 30 min, oil bath heat 3 h under the best conditions can significantly extract lignin, and the yield of lignin is 87.7% and the purity reached 97.3%. The characteristic peaks of FT‐IR confirmed the extraction of lignin. The structural characteristics of 2D‐HSQC also confirmed the effective separation of lignin, and x‐ray diffraction (XRD) and scanning electron microscope (SEM) confirmed the effect of ultrasound‐assisted DES pretreatment on lignocellulose structure. In short, this study provides a feasible method for the separation of lignocellulose.

Urea–choline chloride deep eutectic solvent-assisted synthesis of luminescent nitrogen-doped carbon dots from chitin and their photocatalytic application in decolourizing malachite green

Luminescent carbon dots (CDs) are emerging carbon nanomaterials whose tunable and exceptional optoelectronic properties have found applications as alternatives to traditional fluorophores and metal-based catalysts. Further, they can be easily prepared from biomass and using green solvents. Biomass sources of CDs, however, often result in the formation of thousands of products, which are difficult to separate. In this study, CDs were synthesized using a urea–choline chloride deep eutectic solvent and shrimp shell-derived chitin as raw materials through a low-temperature solvothermal treatment. This was followed by a facile liquid–liquid extraction with acetone to improve the optical properties and narrow the size distribution of the CDs. The acetone-extracted CDs (ACDs) showed good performance in photocatalytic degradation of the aquatic pollutant, malachite green. They also show good potential in monitoring various toxic water pollutants through the quenching effect of selected pesticides, antibiotics, heavy metals, and anions on the fluorescence of ACDs.

An Eutectic Gel Based on Polymerizable Deep Eutectic Solvent with Self‐Adhesive, Self‐adaptive Cold and High Temperature Environments

AbstractIonic conductors have a wide range of development prospects in the field of flexible wearable electronics. The polymerizable deep eutectic solvent is more economical, resistant to extreme temperature, and less toxic than the traditional hydrogels and ionic liquids. In this paper, the supramolecular eutectic gel is prepared by introducing glycol/choline chloride deep eutectic solvent into acrylamide/choline chloride deep eutectic solvent as “hydrogen bond cross‐linking density regulator”. Deep eutectic solvents give eutectic gels the ability to resist the low (‐25 °C) and high (60 °C) temperatures. By introducing 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid into the gel, the adhesion ability of gel on copper sheet can reach 90 kPa and shows good reusability. Due to the complex hydrogen bond interaction in the gel, it has good mechanical properties (strain up to 2300%, stress up to 0.21 MPa). In addition, the ionic conductivity of the gel can reach 0.22 ms cm−1 due to the presence of choline chloride. In addition, since the polymerization is triggered quickly under UV light, this allowed us to print gels of any shape on any surface. Such deep eutectic gels with self‐adhesion, intrinsic conductivity, excellent mechanical properties and extreme temperature resistance may have a wide range of applications in the field of motion sensors.

Two-step separation of lignin from poplar wood powder using malic acid/choline chloride deep eutectic solvents

Deep eutectic solvents (DESs) have been extensively studied for lignin extraction from lignocellulosic biomass due to their easy synthesis, selective lignin dissolution, high recyclability, and other benefits.

Anion dynamics and motional decoupling in a glycerol-choline chloride deep eutectic solvent studied by one- and two-dimensional 35Cl NMR.

Chlorine-35 is among the few nuclides that provide an experimental handle on the anion dynamics in choline based deep eutectic solvents. By combining several nuclear magnetic resonance (NMR) techniques, the present work examines the Cl- motions within glyceline, a glycerol : choline chloride 2 : 1 solution, in a large temperature range down to the glass transition temperature Tg. The applied methods include spin relaxometry, second-order line shape analysis, as well as two-dimensional central-transition exchange and stimulated-echo spectroscopy. The finding of unstructured central-transition NMR spectra characterized by a relatively small average quadrupolar coupling attests to a highly disordered, essentially nondirectional anionic coordination in glyceline. For temperatures larger than about 1.3Tg the chlorine motions are well coupled to those of the glycerol and the choline moieties. At lower temperatures the local translational anion dynamics become Arrhenian and increasingly faster than the motion of glyceline's matrix molecules. Upon further cooling, the overall ionic conductivity continues to display a super-Arrhenius behavior, implying that the choline cations rather than the Cl anions dominate the long-range charge transport also near Tg.