Ionic Liquid Nanoparticles Research Articles

An Ionic Liquid Nanoparticles for Dermal Targeted Delivery and Effective Anti-wrinkle Treatment

BackgroundAging is a natural process that cannot be stopped but retarded. Hydroxypinacolone retinoate (HPR) is a potent anti-wrinkle agent, but with severe irritancy, low stability, and poor water solubility, making it hard to apply in cosmetics. Ionic liquid (IL), as a solvent, displayed improved transdermal efficiency. The role of nano-encapsulation technology in addressing the disadvantages of efficacy application is significant. ObjectiveUsing a combination of ionic liquids and nano-encapsulation technology to obtain HPR-encapsulated ionic liquid nanoparticles (HPR IL-NPs) is an innovative formulation used as a serum, emulsion, and cream in cosmetics for effective anti-wrinkle. MethodsHPR IL-NPs were prepared using matrine coconut oil ionic liquid as a surfactant and permeation enhancer combined with high-pressure homogenization. ResultsThe average particle size in the obtained HPR IL-NPs was 92.8 nm. Applying the HPR IL-NPs increased the content of active substances in the skin by 3.6-fold compared to a traditional HPR-loaded cream. The chick chorioallantois membrane assay showed an RC50 > 100%, and repeated skin-irritation tests resulted in a mean value of 0.00 points per animal per day. The HPR IL-NPs showed continuous release for 24 hours in vitro in the continuous release test. At the same time, the HPR IL-NPs significantly reduced irritation induced by HPR alone. The number and area of facial wrinkles decreased by 25.09% and 23.65%, respectively, after one week of application of liquid cream on volunteers. ConclusionIL NPs can significantly improve transdermal absorption efficiency, reduce irritation, and demonstrate high anti-wrinkle efficiency. Supramolecular liquid cream is a promising product in cosmetics for skin care.

An Exceptional Valorization of CuO Nanoparticles in Ionic Liquids as an Efficient Medium for the Electrophilic Substitution of Indole Towards the Formation of Bis(indolyl)methanes

Aim: Ionic liquids are promising green solvents with simple but unique structure-related physical properties such as negligible vapour pressure, exceptional thermal conductivity, remarkable thermal stability and their suitability and inertness towards a broad range of catalytic applications. CuO NPs have been addressed as a cost-effective and a reagent of a choice that necessitates only mild reaction conditions to offer a high yield of the desired products with exceptional selectivity in a short duration of time. Therefore, in the present work, attempts have been made to explore the catalytic potentials of CuO NPs in an ionic liquid medium to synthesize biologically important bis(indolyl)methanes. Background: Catalytic explorations of metal oxide nanoparticles in ionic liquids offers a cooperative effect that has a significant impact on the kinetics as well as on the outcome of the reaction. Therefore, such catalytic systems in the present times have seized the scientific community's interest from the perspectives of sustainable development in synthetic organic chemistry. The combination of metal oxide nanoparticles with highly tunable ionic liquids is not only used to synthesize simple organic molecules but also explored in the synthesis of complex organic molecules of high commercial and biological relevance. Objectives: The current work offers a rapid and robust protocol for synthesizing bis(indolyl)methanes via electrophilic substitution reaction between indole and various aldehydes in the presence of a CuO nanoparticles-ionic liquid system. The discussion focuses on the high tolerance of different functionalities by the catalytic system leading to the synthesis of bis(indolyl)methanes. Methods: CuO NPs have been synthesized via the co-precipitation method using ionic liquid. The applicability of metal oxide nanoparticles-IL matrix was further investigated in synthesizing bis(indolyl)methanes. Results: The FT-IR absorption below 600 cm-1 and the XRD pattern showing all the peaks in the diffraction diagram revealed the formation of CuO NPs. FESEM images show the flake-shaped morphology of CuO NPs and are found to be separated from the agglomerated clusters Conclusion: Ionic liquid-CuO NPs matrix reveals good to exceptional catalytic properties, and their advancements as a catalytic system at room temperature open new avenues for synthetic organic chemists.

Water-like thermal conductivity of ionanofluids containing high aspect ratio multi-walled carbon nanotubes and 1-ethyl-3-methylimidazolium-based ionic liquids with cyano-functionalized anions

In the era of growing climatic requirements, the search for efficient heat transfer and storage fluids for both industrial and domestic applications is a very important point on the road map of energy transformation in the economies of countries around the world. To achieve the assumed process parameters, working fluids must be characterized by many, often seemingly contradictory, parameters, such as high thermal conductivity and low viscosity, for effective heat transfer. Therefore, the media usually have a very complex structure, which is often designed on the atomic level. An example of such are ionanofluids (INFs) – colloidal dispersions of solid nanoparticles in ionic liquids (ILs). This work aimed to determine the impact and comparison of various cyano-functionalized anions ([SCN]−, [N(CN)2]−, [C(CN)3]−) in 1-ethyl-3-methylimidazolium ([Emim]+) ILs on key properties, such as thermal conductivity, density, viscosity, and structure of INFs, in a wide range of temperature and concentration (up to 10 wt%) of in-house synthesized multi-walled carbon nanotubes (MWCNTs) and carboxyl-functionalized (oxidized) MWCNTs, as well as commercially-available helical carbon nanotubes. Very promising results have been obtained, especially in the case of 1-ethyl-3-methylimidazolium tricyanomethanide [Emim][C(CN)3] with 5.0 wt% loading of ultra-high aspect ratio (up to 11,000) in-house 16 h MWCNTs – thermal conductivity reached 0.532 W·m−1·K−1 at 25 °C which is a threefold improvement (200 %) over the base IL. The thermal conductivity of this value is close to that of water, i.e., an absolute record holder among the conventional heat transfer fluids (0.606 W·m−1·K−1 at 25 °C). The nanofluids were characterized by long-term stability and a wide spectrum of rheological properties, from liquid-like INFs to solid-like ‘bucky gels’, which can be controlled mainly by the morphology and concentration of MWCNTs. For instance, liquid-like [Emim][N(CN)2] + 1.0 wt% in-house 16 h MWCNTs had a viscosity of 34.0 mPa·s (at 186 s−1, 25 °C), which was lower than those of many conventional heat transfer fluids including propylene glycol (42.3 mPa·s, 25 °C), Duratherm® S (49.2 mPa·s, 27 °C), Therminol® 66 (70.8 mPa·s, 27 °C), or Xiameter® PMX-210 (100 mPa·s, 25 °C), while solid-like [Emim][SCN] + 3.0 wt% in-house 16 h MWCNTs had a viscosity up to 8.9 Pa·s (at 18.6 s−1, 25 °C) and may be used in next-generation phase-change materials for efficient thermal energy storage.

Green synthesis of silver nano-catalyst using ionic liquid and their photocatalytic application to the reduction of p-nitrophenol

Ionic liquids (ILs) carrying special properties can act as electronic as well as steric stabilisers by preventing nanoparticle (NP) growth and NP aggregation. The effect of visible light on the catalytic properties of silver nanoparticles is a hot topic of extensive research nowadays. The present report demonstrates the current developments in the green synthesis of silver nanoparticles in ionic liquids and a detailed study of the room-temperature catalytic and photocatalytic reduction of p-nitrophenol (PNP) to p-aminophenol (AP). The Ag nanoparticles (AgNPs) functionalised by ionic liquids are prepared in the 40-140 nm range and are found to be spherical in shape. The photocatalytic properties of these nanocomposites for the reduction of PNP to AP were studied. Photocatalytic degradation of PNP was also analysed by these composite nanostructures. The plasmonic photocatalytic properties of the synthesised AgNPs revealed activity significantly higher than that of the room-temperature catalysis. Density functional theory calculations showed that strong interactions exist between nanoclusters and ILs. Natural bond orbital analysis showed that IL also activates the nanoparticles for further photocatalytic reduction by transferring electron transfer from the donor (IL) to the acceptor (Ag cluster) and activating the silver NPs for further catalytic reaction. Photocatalytic degradation of PNP (reduction of PNP to AP) using NP in the absence of light follows first-order kinetics, whereas in the presence of light it follows zero-order reaction kinetics.

Unified explanation for self-assembly of polymer-brush-modified nanoparticles in ionic liquids

Unified explanation for self-assembly of polymer-brush-modified nanoparticles in ionic liquids

Evaluation of tribological behavior of a circulation oil with ionic liquid and hybrid additives

In this study, the synergistic effects of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888] [NTf2] ionic liquid (IL) with zinc dialkyldithiophosphate (ZDDP) and zinc oxide (ZnO) nanoparticles (NPs) as hybrid additives in a circulation oil for steel–steel contacts at different temperatures. The wear test results indicated that the additions of single additives (IL, ZDDP, and ZnO NPs) could enhance the tribological performance of the circulation oil. Among these additives, the IL exhibited the most effective at the same weight concentration blended into the tested oil. The mixture of IL and ZDDP showed superior friction-reducing and wear-reducing properties compared to the IL + ZnO formulation. The hybrid additive formulation consisting of 0.5 wt% IL, 0.25 wt% ZDDP, and 0.25 wt% ZnO NPs exhibited excellent tribological properties at higher temperatures in the boundary lubrication regime. Analysis using scanning electron microscopy/energy dispersive X-ray reveals that all single additives contribute to the formation of a tribofilm wear mechanism. However, the role of ZnO NPs in the hybrid additive conditions was changed from the most likely tribosintering effect to the most likely nano bearing effect at 100 °C. The interactions among IL, ZDDP, and NPs examined in this study can provide fundamental insights for the development of future lubricants.

Role of alkyl chain present in the cations of ionic liquids on stabilization of silver nanoparticle: DFT and TD-DFT studies

Understanding the preparation and stabilization of silver nanoparticles in ionic liquids is still needed to investigate. Various groups have reported the synthesis and stabilization of silver nanoparticles (Ag NPs) in ionic liquids (ILs) on varying the cation and anion. There is a need to understand the impact of alkyl chain present in the cation to understand the new interactions between the ILs with Ag NPs. Herein, the authors have designed the imidazolium ring based ionic liquids having tetrafluoroborate (TFB) as anion and the alkyl chain present on the cation is varied. The interactions have been studied through the DFT and TD-DFT calculations performed by Gaussian. Herein, free energy and other thermodynamic parameters of ILs with and without Ag are calculated. It came to know that the change in free energy for 3-Ag is least among all designed. 1-Ag is least stable as the change in free energy is positive at 298 K. On varying the alkyl chain, different types of interactions are observed. The same can be seen by localization of nucleophilic and electrophilic sites in the HOMO and LUMO of the ILs with and without Ag. Further, their dipole moments are also determined to understand the polarity of ILs with and without Ag and herein, no regular pattern is observed.

Influence of cation (imidazolium based ionic liquids) as “smart” stabilizers for silver nanoparticles and their evaluation as antibacterial activity on Escherichia coli, Staphylococcus aureus and Enterobacter cloacae

Ionic liquids (ILs) represent versatile solvents and green milieu for the growth and stabilisation of metal nanoparticles. The current study reports the synthesis of silver nanoparticles in ILs based on two different cations, namely 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]). The prepared nanoparticles were characterised by dynamic light scattering, SEM imaging, UV–vis, FTIR, and zeta potential spectral data. The in vitro antibacterial activity of the as-developed nanomaterials was assessed against three bacterial pathogens, including Escherichia coli, Staphylococcus aureus, and Enterobacter cloacae. The results obtained indicate negatively charged and stable nanoparticles with average sizes of 132 nm for Ag NPs-[EMIM][BF4] and 360 nm for Ag NPs-[BMIM][BF4]. The nanoparticles Ag NPs-[BMIM][BF4] and Ag NPs-[EMIM][BF4] exhibited moderate antibacterial activity against E. coli (MIC: 62.5 and 125 µg/ml, respectively) and E. cloacae (MIC: 125 and 250 µg/ml, respectively). Against S. aureus, Ag NPs-[BMIM][BF4] afforded MIC value of 125 µg/ml, suggesting that these particles also possess moderate anti-staphylococcal activity. Further, molecular docking of [BMIM][BF4]) and [EMIM][BF4] with and without Ag against PDB ID: 1C21 and 1JIJ was performed. This computer-aided technique was complemented with DFT calculations to check the thermodynamic properties of ILs with and without Ag. The nature of the alkyl sidechains (1-butyl vs 1-ethyl groups) on the cation might play a crucial role in elevating the antibacterial activity of these nanoparticles.

Ion channels in sulfonated copolymer-grafted nanoparticles in ionic liquids.

The use of ionic liquids as solvents for polymers or polymer-grafted nanoparticles provides an exciting feature to explore electrolyte-polymer interactions. 1-Hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIm-TFSI) can have specific interactions with the polymer through ion-dipole forces or hydrogen bonding. In this work, poly(methyl methacrylate)-b-poly(styrene sulfonate) (PMMA-b-PSS) copolymer-grafted Fe3O4 nanoparticles with different sulfonation levels (∼4.9 to 10.9 mol% SS) were synthesized, and their concentration dependent ionic conductivities were reported in acetonitrile and HMIm-TFSI/acetonitrile mixtures. We found that conductivity enhancement with the particle concentration in acetonitrile was due to the aggregation of grafted particles, resulting in sulfonic domain connectivity. The ionic conductivity was found to be related to the effective hopping transfer within ionic channels. On the contrary, the conductivity decreased or remained constant with increasing particle concentration in HMIm-TFSI/acetonitrile. This result was attributed to the ion coupling between ionic liquids and copolymer domains.

Colloids of HEA nanoparticles in an imidazolium-based ionic liquid prepared by magnetron sputtering: Structural and magnetic properties

Colloids consisting of the CoCrCuFeNi high-entropy alloy nanoparticles in ionic liquid with the 1-butyl-3-methylimidazolium ([BMIM]+) cation and the tetrafluorborate ([BF4]-) anion were obtained by the DC magnetron sputtering of high-entropy alloy target in vacuum, onto the surface of [BMIM.BF4] ionic liquid. The method of the nanoparticle colloid preparation is based on negligibly small vapour pressure of the ionic liquid, which allows its application in vacuum. The high-entropy alloy nanoparticle colloids were studied by HRTEM microscopy and SQUID magnetometry. Results of the structural and magnetic analyses show that the colloids contain ultra-small single-crystalline nanoparticles of an uneven shape and typical size of (2−3) nm. The nanoparticles have relatively narrow size distribution which is typical for this preparation method. The high-entropy alloy nanocolloids show complex magnetic properties that are a function of temperature, applied magnetic field and mass content of the nanoparticles in the colloids. The obtained results imply significant magnetic interactions between the ionic liquid and the high-entropy alloy nanoparticles.

A new expeditious synthesis of the core scaffold of salvianolic acid F trough a one-pot sequential Heck coupling catalyzed by palladium nanoparticles in ionic liquids

A new expeditious synthesis of tetramethyl salvianolic acid F is presented. Starting from the naturally occurring veratrole, the target molecule is easily obtained in a one-pot mode via a sequential double Heck coupling catalyzed by palladium nanoparticles dispersed in ionic liquids. The present method involves the chemoselective displacement of two different halogen atoms present on the veratrole ring and limits the need for tedious experimental procedures. A 66% of overall yield can be achieved, that represents, as far as we know, one of the best results present in the literature, until now. This protocol can also open the way for the synthesis of unnatural salvianolic-like compounds with potential bioactivity.

Metal nanoparticles in ionic liquids: Synthesis and catalytic applications

• Nanoparticles of many metals can be obtained in ionic liquids by physical, chemical, and electrochemical methods. • The ionic liquids medium stabilizes metal nanoparticles without additional stabilizers, surfactants, or capping ligand. • Ionic liquids allow to control the size and shape of metal nanoparticles thus improving their catalytic activity. • Electrochemical approaches allow a smart control of the size, shape, and crystal structure of metal nanoparticles. • Applications of metal nanoparticles in catalysis provide a driving force for developing new nanoscale materials. The development of metal nanoparticle chemistry in ionic liquids (ILs) media has had a paramount impact on various fields, including catalysis, energy research, nanotechnology and materials science, among many other directions. This review highlights various methods for producing metal nanoparticles in ILs, with particular focus on palladium, platinum, ruthenium, copper, nickel, cobalt, gold, silver, iron and alloys. The scope of methods includes chemical syntheses as well as electrochemical and physical approaches. Due to strong practical demand, a particular emphasis is placed on the catalytic activity of the obtained nanoparticles in a variety of reactions.

Design of concentrated colloidal dispersions of iron oxide nanoparticles in ionic liquids: Structure and thermal stability from 25 to 200 °C

HypothesisSome of the most promising fields of application of ionic liquid-based colloids imply elevated temperatures. Their careful design and analysis is therefore essential. We assume that tuning the structure of the nanoparticle-ionic liquid interface through its composition can ensure colloidal stability for a wide temperature range, from room temperature up to 200 °C. ExperimentsThe system under study consists of iron oxide nanoparticles (NPs) dispersed in ethylmethylimidazolium bistriflimide (EMIM TFSI). The key parameters of the solid-liquid interface, tuned at room temperature, are the surface charge density and the nature of the counterions. The thermal stability of these nanoparticle dispersions is then analysed on the short and long term up to 200 °C. A multiscale analysis is performed combining dynamic light scattering (DLS), small angle X-ray/neutron scattering (SAXS/SANS) and thermogravimetric analysis (TGA). FindingsFollowing the proposed approach with a careful choice of the species at the solid-liquid interface, ionic liquid-based colloidal dispersions of iron oxide NPs in EMIM TFSI stable over years at room temperature can be obtained, also stable at least over days up to 200 °C and NPs concentrations up to 12 vol% (≈30 wt%) thanks to few near-surface ionic layers.

Design of bimetallic Au/Cu nanoparticles in ionic liquids: Synthesis and catalytic properties in 5‐(hydroxymethyl)furfural oxidation

AbstractIn alloyed nanoparticles, synergistic electronic and/or geometric effects may enhance the catalytic properties compared to their monometallic counterparts. Herein, we address the synthesis of bimetallic Au/Cu nanoparticles with different compositions by wet chemical reduction in ionic liquids. The nanoparticles were successively supported on carbon. The ionic liquid could be recycled after synthesis. Annealing of the carbon‐supported NPs at 400 °C led to NPs of the ordered intermetallic L10 AuCu phase. The nanoparticle‐derived catalysts were characterized by X‐ray diffraction analysis, transmission electron microscopy, X‐ray photoelectron spectroscopy and optical emission spectroscopy with inductively coupled plasma. Oxidation of biomass‐derived furans is a prominent process for biomass transformation into value‐added chemicals. Herein, the oxidation of 5‐hydroxymethyl‐2‐furfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) was chosen as a model reaction to evaluate the effect of Cu addition and intermetallic structure on the catalytic performance. Particularly Au/Cu nanoparticles with an Au/Cu ratio of 3 : 1 showed very high conversion to FDCA.

Ion-Containing Polymer-Grafted Nanoparticles in Ionic Liquids: Implications for Polymer Electrolyte Membranes

Ion-Containing Polymer-Grafted Nanoparticles in Ionic Liquids: Implications for Polymer Electrolyte Membranes

Bimetallic RuPd nanoparticles in ionic liquids: selective catalysts for the hydrogenation of aromatic compounds

Bimetallic RuPd nanoparticles are effective catalysts for the hydrogenation of aromatic compounds and the activity and selectivity depend on the Ru : Pd ratio.

Thermophysical Properties of IoNanofluids Composed of 1-ethyl-3-methylimidazolium Thiocyanate and Carboxyl-functionalized Long Multi-walled Carbon Nanotubes

The concept of IoNanofluids (INFs) as the stable dispersions of nanoparticles in ionic liquids was proposed in 2009 by Nieto de Castro’s group. INFs characterize exciting properties such as improved thermal conductivity, non-volatility, and non-flammability. This work is a continuation of our studies on the morphology and physicochemistry of carbon-based nanomaterials affecting thermal conductivity, viscosity, and density of INFs. We focus on the characterization of dispersions composed of long carboxylic group-functionalized multi-walled carbon nanotubes and 1-ethyl-3-methylimidazolium thiocyanate. The thermal conductivity of INFs was measured using KD2 Pro Thermal Properties Analyzer (Decagon Devices Inc., Pullman, WA, USA). The viscosity was investigated using rotary viscometer LV DV-II+Pro (Brookfield Engineering, Middleboro, MA, USA). The density of INFs was measured using a vibrating tube densimeter Anton Paar DMA 5000 (Graz, Austria). The maximum thermal conductivity enhancement of 22% was observed for INF composed of 1 wt% long carboxylic group-functionalized multi-walled carbon nanotubes.

Designing Structurally Ordered Pt/Sn Nanoparticles in Ionic Liquids and their Enhanced Catalytic Performance

AbstractMultimetallic nanoparticles (NPs) often exhibit enhanced catalytic properties that differ from their parent materials. Carefully exploring the structures of multimetallic NPs is a prerequisite for understanding the structure‐ and composition‐associated properties. Herein, intermetallic Pt/Sn NPs with tunable compositions are designed exploiting the beneficial properties of ionic liquids (ILs) in a one‐pot synthetic procedure. Metal salt precursors are reduced with triethylhydridoborate, whereby the cation of the triethylhydridoborate is adapted to the cation of the IL. Both the initial metal precursor ratio and the type of IL influence the structure of the NPs, with the effect of the IL being more pronounced. PtSn nanocrystals are obtained as phase pure products under optimized reaction conditions, whereby a microwave‐assisted approach leads to higher crystallinity. In the hydrogenation of α,β‐unsaturated aldehydes, the catalytic performance obviously depend on the NP composition. In bimetallic Pt/Sn NPs, higher Pt content leads to increased conversion, while increase in Sn increases selectivity to the cinnamic alcohol.

Ionic liquid functionalized 3D graphene-carbon nanotubes‒AuPd nanoparticles‒molecularly imprinted copolymer based paracetamol electrochemical sensor: Preparation, characterization and application

An innovative electrochemical sensor for paracetamol (PCM) determination was fabricated by electropolymerization imprinting on three-dimension (3D) AuPd nanoparticles‒ionic liquid (IL) functionalized graphene‒carbon nanotubes nanocomposite (AuPd/GN-CNTs-IL) modified glassy carbon electrode. The GN-CNTs supported AuPd alloy nanoparticles were prepared via one-pot hydrothermal method in the presence of IL (i.e. 1-hydroxyethyl-3-methyl imidazolium bis[(trifluoromethyl) sulfonyl] imide), which not only promoted the formation of small AuPd alloy nanoparticles, but also acted as “spacer” to prevent the π-π stacking and aggregation of graphene sheets and carbon nanotubes. The resulting composite had large surface area and high electrocatalysis. The PCM imprinted poly(carbazole-co-pyrrole) exhibited good recognition to PCM and had high stability. Based on the synergic effect of PCM imprinted copolymer and 3D AuPd/GN-CNTs-IL nanocomposite, a highly selective and sensitive electrochemical sensor was established. It presented a good linear relationship from 0.10 to 10 μM with a low limit of detection of 50 nM (S/N = 3). The sensor could be applied to the detection of PCM in biological samples, with acceptable recoveries (84.5%–102%). In addition, it was successfully used to monitor the concentration of PCM in urine from a patient with fever cold.

Heteroatom-Doped Carbon Nanoparticle–Ionic Liquid Composites as Electrochemical Sensors for Uric Acid

We reported the fabrication of an electrochemical sensor for uric acid (UA) monitoring using metal-free electrode based on heteroatoms (S, N, P, and O) doped carbon (HADC) nanoparticles, derived from polyphosphazene, synthesized via precipitation polymerization reaction between hexachlorocyclotriphosphazene (HCCP) and 1,4-dithiane-2,5-diol (DD) under sonication irradiations at 40 °C, following its modification with benzimidazolium-1-acetate ionic liquid (BIL). The developed HADC-BIL electrode showed a highly sensitive and selective response toward UA even in the presence of highly electroactive interferences such as ascorbic acid (AA), dopamine (DA), glucose (Glu), and hydrogen peroxide (H2O2). Our results demonstrated that the as-fabricated HADC-BIL electrode allows us to detect UA over a linear range of 2–1050 μM with a detection limit of 1.27 μM. Further, we were able to monitor the amount of UA level in the blood of a gout patient using the developed HADC-BIL electrode, which ensures the effectiveness of the developed sensor for the sensitive and selective detection of UA from real samples.