Phosphonium-based Ionic Liquids Research Articles

Effects of Water Content on the Transport and Thermodynamic Properties of Phosphonium Ionic Liquids.

We present a numerical investigation of the influence of water content on the dynamic properties of a family of phosphonium-based room-temperature ionic liquids. The study presents a compelling correlation between structural changes in water-ionic liquid solutions and thermodynamic and transport properties across diverse systems. The results for phosphonium ionic liquids are compared with 1-butyl-3-methylimidazolium hexaphosphate ([bmim]PF6) as a reference. Through this approach, phosphonium cation structure-related characteristics can be identified and placed within the broader context of ionic liquids. These insights are underpinned by observed changes in interaction energy, boiling point, diffusion rate, and viscosity, highlighting the crucial role of water molecules in weakening the strength of interactions between ions within the ionic liquid. The investigation also explains temperature-dependent trends in phosphonium cations, showing that alkyl group length and molecular symmetry are important tuning parameters for the strength of Coulomb interactions. These results contribute to a refined understanding of phosphonium ionic liquid behavior in the presence of water, offering valuable insights for optimizing their use in diverse fields.

Cation Chain Length of Nonhalogenated Ionic Liquids Matters in Enhancing SERS of Cytochrome c on Zr-Al-Co-O Nanotube Arrays.

Surface-enhanced Raman scattering (SERS) is a remarkably powerful analytical technique enabling trace-level detection of biological molecules. The interaction of a probe molecule with the SERS substrate shows important distinctions in the SERS spectra, providing inherent fingerprint information on the probe molecule. Herein, nonhalogenated phosphonium-based ionic liquids (ILs) containing cations with varying chain lengths were used as trace additives to amplify the interaction between the cytochrome c (Cyt c) and Zr-Al-Co-O (ZACO) nanotube arrays, strengthening the SERS signals. An increased enhancement factor (EF) by 2.5-41.2 times compared with the system without ILs was achieved. The improvement of the SERS sensitivity with the introduction of these ILs is strongly dependent on the cation chain length, in which the increasing magnitude of EF is more pronounced in the system with a longer alkyl chain length on the cation. Comparing the interaction forces measured by Cyt c-grafted atomic force microscopy (AFM) probes on ZACO substrates with those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the van der Waals forces became increasingly dominant as the chain length of the cations increased, associated with stronger Cyt c-ZACO XDLVO interaction forces. The major contributing component, van der Waals force, stems from the longer cation chains of the IL, which act as a bridge to connect Cyt c and the ZACO substrate, promoting the anchoring of the Cyt c molecules onto the substrate, thereby benefiting SERS enhancement.

Absorption performance and mechanism of volatile organic compounds by phosphonium ionic liquids with different anions

AbstractBACKGROUNDThe emission of volatile organic compounds (VOCs) seriously harms the environment and human health. The prevention and control of VOCs pollution is a major challenge in the research field. Aiming at VOCs pollution treatment using green solvents, the absorptions of trichloromethane by synthesized tributyl(propyl)phosphonium bis(trifluoromethylsulfonyl)imide ([P4443][Tf2N]), tributyl(propyl)phosphonium tetrafluoroborate ([P4443][BF4]), tributyl(propyl)phosphonium trifluoroacetic acid ([P4443][CF3COO]) and xylene by trioctyl(propyl)phosphonium bis(trifluoromethylsulfonyl)imide ([P8883][Tf2N]) and trioctyl(propyl)phosphonium tetrafluoroborate ([P8883][BF4]) were experimentally measured. The mechanism of trichloromethane and xylene being absorbed by PILs with different anions was further discussed through simulation calculation.RESULTSThe phosphonium‐based ionic liquids (PILs) process excellent absorption capacity, such as [P4443][CF3COO] with the static saturation absorbing capacity up to 2.843 g/g for trichloromethane. PILs have a certain selective absorption ability for xylene, which has the highest absorption for o‐xylene reaching 1.462 g/g. The absorption energy data also prove that [CF3COO]− anion preferentially interacts with trichloromethane. Combine with the most stable structures of VOCs absorbed by PILs, the results of the Mulliken charge and frontier molecular orbitals indicate that PILs anions play a major role in chlorinated alkanes, and form hydrogen bonds with them. In addition, the cation can form C‐H…π bond interaction with xylene.CONCLUSIONThe experimental and calculated results showed that PILs is a promising adsorbent for trichloromethane and xylene. It provides reference for PILs designed to deal with VOCs in the future.This article is protected by copyright. All rights reserved.

Biocompatible tetrabutylphosphonium-based ionic liquids with medium-chain fatty acids as anions: Thermo-physical and antimicrobial profile

The importance of developing effective antimicrobial agents has become more evident recently, and quaternary phosphonium-based ionic liquids with fatty acid anions have shown great potential in this regard. Tetrabutylphosphonium-hexanoate, -octanoate, -decanoate, and -dodecanoate were synthesized as potential antimicrobial ionic liquids. Confirmation of the structure of the synthesized ionic liquids was determined by IR and NMR spectroscopy. Also, the thermal stability was examined by thermogravimetric (TG) and differential scanning calorimetry (DSC) analysis. Physicochemical characterization was carried out, which included the measurement of density, viscosity, and electrical conductivity in a wide temperature range to understand the interactions that occur in synthesized ionic liquids. The antimicrobial activity against various microorganisms was determined, including three Gram-negative and Gram-positive bacteria, two yeast, and four filamentous fungal strains. Based on the results, ILs were more efficient against Gram-positive than Gram-negative bacteria, whereby the longest-chained anion contributes to the best antibacterial activity. Yeast Candida guillermondii and all tested filamentous fungi were most sensitive to tetrabutylphosphonium-decanoate.

Extractive desulfurization of crude petroleum oil and liquid fuels using trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate ionic liquid

Abstract Increasing environmental concerns have led to the development of alternative methods for the desulfurization of petroleum crude oil and liquid fuels. Phosphonium-based ionic liquids (PILs) have recently demonstrated promising potential for effective extractive desulfurization (EDS). The present study focuses on the synthesis and application of trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate [THTDP][D2EHP] for EDS of synthetic model fuels and real crude oils. The molecular confirmation and thermal stability of [THTDP][D2EHP] were investigated using FTIR and TGA analyses. In addition, the conductivity, solubility, and viscosity of the synthesized ionic liquid (IL) were analyzed. The impact of reaction time, temperature, and sulfur compounds, such as thiophene, benzothiophene, and dibenzothiophene (DBT), on the desulfurization efficiency from synthetic fuels was also investigated. The results indicated up to 63 and 57 % sulfur removal from DBT-based model fuels and Iranian crude oil, respectively. The optimum extraction conditions were found as 1:1 IL/fuel mass ratio, 35 °C, and 30 min. The findings of this study provide valuable insights into the synthesis and utilization of PILs as promising solvents for extractive desulfurization of crude oil and liquid fuels.

Computational study on organochlorine insecticides extraction using ionic liquids

Insecticides pose hazardous environmental effects and can enter the food chain and contaminate water resources. Ionic liquids (ILs) have recently drawn much interest as environmentally friendly solvents and have been an efficient choice for extracting pesticides because of their outstanding thermophysical characteristics and tunable nature. In this study, ILs were screened using COSMO-RS (Conductor-like Screening Model for Real Solvents) to extract organochlorine insecticides from water at 289 K. A total of 165 ILs, a combination of 33 cations with five anions, were screened by COSMO-RS to predict the selectivity and capacity of the organochlorine insecticides at infinite dilution. The Organochlorine insecticide compounds, such as benzene hexachloride (BHC), Heptachlor, Aldrin, Gamma-Chlordane (γ-Chlordane), Endrin, and Methoxychlor are selected for this study. Charge density profiles show that Endrin and Methoxychlor compounds are strong H-bond acceptors and weak H-bond donors, while the rest of the compounds are H-bond donors with no H-bond acceptor potential. Moreover, it has been shown that ILs composed of halides and heteroatomic anions in conjunction with cations have enhanced selectivity and capacity for insecticides. Moreover, the hydrophobic phosphonium-based ILs have enhanced selectivity and capacity for insecticides. In BHC extraction, the selectivity of 1,3-dimethyl-imidazolium chloride was found to be the highest at 1074.06, whereas 2-hydroxyethyl trimethyl ammonium chloride exhibited the highest capacity being 84.0.1,3-dimethyl-imidazolium chloride exhibits the highest performance index, which is 57064.77. In addition, the ILs that have been chosen are well-recognized as environmentally friendly and very effective solvents to extract insecticides from water. As a result, this study evaluated that ILs could be promising solvents that may be further developed for the extraction of insecticides from contaminated water.

Density, viscosity, and CO2 solubility in ether-functionalized phosphonium-based bis(trifluoromethanesulfonyl)amide ionic liquids

We measured the densities and viscosities of two ionic liquids, triethyl(methoxymethyl)phosphonium bis(trifluoromethanesulfonyl)amide ([P222(1O1)][TFSA]) and triethyl(2-methoxyethyl)phosphonium bis(trifluoromethanesulfonyl)amide ([P222(2O1)][TFSA]), at atmospheric pressure and 273.15–363.15 K. The high-pressure density at the pressures up to 50 MPa was also measured at 298.15–353.15 K. Meanwhile, CO2 solubility in these phosphonium-based ionic liquids was determined using a magnetic suspension balance at 303.15–333.15 K and pressures up to 6 MPa. The experimental density and viscosity at atmospheric pressure were fitted using quadratic and Vogel-Fulcher-Tammann equations, respectively. The high-pressure density was fitted using the Tait equation and Sanchez-Lacombe equation of state. The properties of the two ether-functionalized ionic liquids were compared to those of triethylpentylphosphonium bis(trifluoromethanesulfonyl)amide [P2225][TFSA]. The density at atmospheric pressure increased in the order [P2225][TFSA] < [P222(2O1)][TFSA] < [P222(1O1)][TFSA]. The introduction of the ether group effectively reduced viscosity in the following order: [P222(1O1)][TFSA] < [P222(2O1)][TFSA] < [P2225][TFSA]. The CO2 solubilities in [P222(1O1)][TFSA] and [P222(2O1)][TFSA] were slightly lower than those in [P2225][TFSA]. In contrast, the molality of CO2 (m1) increased in the order [P2225][TFSA] < [P222(2O1)][TFSA] < [P222(1O1)][TFSA]. Ether functionalized phosphonium-based cations are effective in enhancing the physical absorption of CO2, particularly the molality of CO2.

Study of the molecular interaction of a phosphonium-based ionic liquid within myo-inositol and non-steroidal anti-inflammatory drugs.

Ionic liquids (ILs) can be used as carriers and solubilizers as well as for increasing the effectiveness of drugs. In the present investigation, the micellar properties of phosphonium-based ionic liquids (PILs) such as trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate ([P666(14)][THPP]) and the effect of carbocyclic sugar-based myo-inositol (MI) and non-steroidal anti-inflammatory drugs (NSAIDs), i.e. ibuprofen (IBU) or aspirin (ASP), on the PIL micellar system were studied using surface tension, conductivity, colorimetry, viscometry, FTIR, and dynamic light scattering (DLS) at a temperature of 299 ± 0.5 K. The critical micelle concentrations (CMCs), particle size, zeta potential, and various interfacial parameters were also included i.e., efficiency of adsorption (pC20), surface tension at CMC (γCMC), minimum surface area per molecule (Amin), surface pressure at CMC (πCMC), maximum surface excess concentration (Γmax), and various thermodynamic parameters, such as standard Gibbs free energy of adsorption , standard Gibbs free energy of micellization per alkyl tail , standard Gibbs free energy of the air-water interface (ΔG(s)min), standard Gibbs free energy of transfer , and standard Gibbs free energy of micellization . The adsorption and micellization characteristics became more spontaneous, as shown by the more negative values of and . Viscosity-based rheological properties were calculated for various PIL + MI and PIL + MI + NSAID systems. According to the DLS data, the PIL (Z = 316.4 nm) micellar system generates substantially bigger micelles in an aqueous solution of MI + ASP (Z = 801.7 nm) than in MI + IBU (Z = 674.7 nm). FTIR spectroscopy revealed the interactions of PIL with MI + ASP and MI + IBU, where it was observed that MI + IBU shows good agreement with the PIL system compared to MI + ASP. The current research will have effects on pharmaceutical sciences, molecular biology, and drug delivery.

Physicochemical and Thermodynamic Investigation of Ethanolic Solution of Phosphonium-Based Ionic Liquids─Measurements, Correlations, and Application to Absorption Cycles

Physicochemical and Thermodynamic Investigation of Ethanolic Solution of Phosphonium-Based Ionic Liquids─Measurements, Correlations, and Application to Absorption Cycles

Effect of the anion in phosphonium-based ionic liquids to recovery efficiently 2-propanol from an azeotropic mixture with water

Effect of the anion in phosphonium-based ionic liquids to recovery efficiently 2-propanol from an azeotropic mixture with water

Effect of phosphonium‐based ionic liquids on the structuration and physical properties of LIonomers

AbstractIn this study, LIonomers families based on phosphonium ILs have been successfully developed. These LIonomers are designed from the combination of various phosphonium‐based ionic liquids (PhILs) with different counter anions including tetradecyl (trihexyl) phosphonium bis (2,4,4‐trimethylpentyl) phosphinate (P+TMP), tributyl (ethyl) phosphonium diethyl phosphate (P+DEP), trihexyl (tetradecyl) phosphonium chloride (P+Cl) and trihexyl (tetradecyl) phosphonium acetate (P+Ac). Here, the interactions between maleic anhydride groups (MA) of the maleic anhydride‐grafted polypropylene (PPgMA) and PhILs within LIonomers have been investigated by NMR, whose intensity depends on the chemical nature of cation/anion pairs. Then, viscosity in the molten state was considered as a probe of the interaction intensity between polar groups of grafted polypropylenes and the phosphonium cation. The proper one can be tuned from the nature (P+TMP vs. P+Ac vs. P+Cl), from the steric hindrance, that is, relevant to the conformation of PhILs (P+DEP vs. P+TMP / P+Ac / P+Cl), and by MA content, as well as the extent of generated ionic chains from polar groups of matrices as “head” and associated anion/cation pairs. The effect of these generated ionic interactions on crystallization process and mechanical properties had been also investigated by DSC in non‐isothermal conditions, and tensile tests. Depending of the steric hindrance of the phosphonium ILs playing a key role on the interactions with PPgMA chains, an increase of the ductility versus a plasticizing effect can be obtained as function of the targeted applications.

Preparation and Physicochemical Characterization of Phosphonium-Based Ionic Liquids Containing Carboxylate Anions

Ionic liquids (ILs) are organic salts composed of cation and anion with melting points below 100°C. They have unique characteristic features.1) ILs are also promising liquid materials available for various applications because their function can be easily controlled by changing the combination of cations and anions and by introducing substituents. Among the numerous ILs, considerable ILs based on carboxylate anions have been reported. On the other hand, several published papers reported ILs based on quaternary phosphonium cations, demonstrating relatively high transport properties and thermal stability2). We report here the preparation and physicochemical properties of ILs based on triethyloctylphosphonium (P2228) and tributyloctylphosphonium (P4448) cations together with various carboxylate anions.The intermediate hydroxides were obtained by adding an anion exchange resin (Amberlite IRN78 OH) into the precursor bromide aqueous solutions. Equimolar amounts of carboxylic acids (formic, acetic, propionic, butyric and octanoic acids) were added to the hydroxide solutions to form carboxylate-based phosphonium salts. The salts obtained were isolated by evaporation and then were dried under high vacuum at 50 °C. The physicochemical properties of ILs, e.g. density, viscosity, conductivity and thermal decomposition temperature were measured.Table 1 shows the physicochemical properties of the ILs at 25 °C. P2228-PrCO2 became a solid at room temperature, while P2228-HCO2, P2228-MeCO2, and P2228-EtCO2 became viscous liquids at room temperature. Furthermore, all P4448-based salts became viscous liquids at room temperature. The density of each IL was increased with decreasing the carbon numbers of the alkyl chains in carboxylate anions. The number density also showed similar tendency to the density. These results indicate that the number density of the formate was the highest since the anion size was the smallest. The viscosity of each ILs was decreased with increasing the carbon numbers of the alkyl chains in carboxylate anions. Although the details of the relationship between measured viscosity and the carbon numbers of the alkyl chains in carboxylate anions still remain unclear at present, it is thought to be the charge distribution of the anions is one of the factors. The acetate-, propionate-, butyrate-, and octanoate-based ILs showed high thermal decomposition temperatures around 270 to 300°C. However, the formate-based ionic liquid showed lower thermal stability, which might be due to the decarboxylation of the formate anion. Figure 1

Molecular simulation of CO2 capturing by dual functionalized phosphonium-based amino acid ionic liquids

Various solvents have been proposed considering the importance of CO2 gas removal from the environment. Over the past few decades, ionic liquids (ILs) have elicited much attention due to their unique properties. In this regard, capturing the CO2 gas by phosphonium-based amino acid ILs (AAILs) was studied by molecular dynamics (MD) simulation. The effect of cation functionalization was studied. The anion was glycinate, [GLY]-, and the cation was tetrabutylphosphonium, [P4444]+, functionalized by different functional groups including acidic (−COOH), alcoholic (−OH), amine (−ΝΗ2), and ether (−OCH3). Density, absorption energy, radial distribution function (RDF), mean square displacement (MSD), concentration profile, free volume, and fractional free volume were under investigation. According to density values calculated from MD simulation, functionalized AAIL with a carboxylic acid group ([P4444COOH][Gly]) is the most concentrated system with the maximum interaction energy between AAIL and the trapped CO2 gas equal to − 1.917 kcal.mol−1. In addition, the lowest volume variation was observed through this physical absorption. RDF analysis reveals that anion interaction with CO2 gas is the most considerable one in the case of [P4444COOH][Gly] AAIL. The CO2 uptake is 2:1 for functionalized AAILs that shows cation functionalization improves CO2 gas absorption capacity; each mole of [P4444COOH][Gly] AAIL is capable of surrounding 2.11 mol of CO2. Finally, the gas diffusion coefficient is the lowest one in [P4444COOH][Gly] AAIL as the solvent-free volume is observed as a continuous channel to trap CO2 gas with the lowest gas diffusivity parameter.

Selective extraction of Ti(IV) from acidic sulfate media by phosphonium-based ionic liquids and stripping with sulfuric acid

The Ti(IV) liquid-liquid extraction from acidic sulfate media has been investigated by the ionic liquids trihexyl(tetradecyl)phosphonium chloride [P66614+][Cl−] and trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate [P66614+][BTMPP−], diluted in 5% (v/v) 1-decanol/kerosene. The Room Temperature Ionic Liquids (RTIL) showed fast extraction kinetics reaching equilibration after 2 min, requiring a 450 rpm stirring rate. For [P66614+][Cl−] at 0.01 mol L−1, the maximum extraction efficiency was 30% from H2SO4 solution of 11 mol L−1. The IL [P66614+][BTMPP−] shows better Ti(IV) extraction than [P66614+][Cl−], and two maximum extraction conditions were observed at 0.1 and 7.3 mol L−1 H2SO4 due to the dual mechanism; both cationic and anionic exchange reactions, reaching 60% and 49% extraction efficiency, respectively.The increase in [P66614+][BTMPP−] concentration to 0.06 mol L−1, increases the extraction yield to 95.9%. The Fourier transform infrared FTIR characterization confirmed the presence of Ti(IV) in the organic phases, and the modification in the phosphonium bonds was correlated to the role of the ionic liquids in the Ti(IV) extraction. The organic phase containing 0.02 mol L−1 [P66614+][BTMPP−] can be loaded with 0.197 g/L of Ti(IV) from 7.3 mol L−1 H2SO4 media. In contrast, at 0.1 mol L−1 H2SO4, an increase in the Ti(IV) concentration promotes the polymerization in the form Ti-O-Ti-O-Ti inhibiting the extraction efficiency. The H2SO4 solution at 2 mol L−1 was the best stripping agent to achieve a high Ti(IV) recovery of 97%. The organic phase was reused for four cycles, and the extraction and stripping efficiencies remained unchanged after the third cycle. The selective separation of Ti(IV) from a mixture containing Fe(III) was reached with a separation factor of 78.4, with a 2.51% Fe(III) extraction and containing only 0.25 mg L−1 of Fe(III) in the stripping phase. The proposed system avoids the main problems associated with Ti(IV) recovery from acidic sulfate media.

Effect of surface wetting on tribological behavior for laser textured steel using ionic liquid-based lubricants

In this study, the effect of surface wettability on the tribological performance is evaluated through a ball-on-flat reciprocating wear test. The substrate material, M2 tool steel, is laser processed and then functionalized with fluorocarbon and nitrile chemistry to achieve distinct oleophobicity and oleophilicity, respectively, but with a similar nanoscale surface texture. The poly-alpha-olefin (PAO) base oil is used as the baseline lubricant, and ammonium- and phosphonium-based oil-miscible ionic liquids (ILs) are used as additives. The interaction between the nanoscale textured steel surface and ionic liquid-based oils is investigated. A set of reciprocating wear tests are performed to identify the wear and frictional mechanisms of the tribosystem consisting of the surface-engineered, flat M2 tool steel specimen and a standard, surface-polished steel ball. Results show that the oleophobic flat surface results in a lower friction, while the oleophilic surface modification leads to a better wear protection to the flat surface. Ammonium-based IL provides the highest friction reduction, while the phosphonium-based IL provide an improved wear protection. Click here and insert your abstract text.© 2023 Society of Manufacturing Engineers (SME). Published by Elsevier Ltd. All rights reserved.This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under responsibility of the Scientific Committee of the NAMRI/SME.

Change of Conduction Mechanism in Polymer/Single Wall Carbon Nanotube Composites upon Introduction of Ionic Liquids and Their Investigation by Transient Absorption Spectroscopy: Implication for Thermoelectric Applications.

Polymer composites based on polycarbonate (PC) and polyether ether ketone (PEEK) filled with single-walled carbon nanotubes (SWCNTs, 0.5-2.0 wt %) were melt-mixed to investigate their suitability for thermoelectric applications. Both types of polymer composites exhibited positive Seebeck coefficients (S), indicative for p-type thermoelectric materials. As an additive to improve the thermoelectric performance, three different ionic liquids (ILs), specifically THTDPCl, BMIMPF6, and OMIMCl, were added with the aim to change the thermoelectric conduction type of the composites from p-type to n-type. It was found that in both composite types, among the three ILs employed, only the phosphonium-based IL THTDPCl was able to activate the p- to n-type switching. Moreover, it is revealed that for the thermoelectric parameters and performance, the SWCNT:lL ratio plays a role. In the selected systems, S-values between 61.3 μV/K (PEEK/0.75 wt % SWCNT) and -37.1 μV/K (PEEK/0.75 wt % SWCNT + 3 wt % THTDPCl) were reached. In order to shed light on the physical origins of the thermoelectric properties, the PC-based composites were studied using ultrafast laser time-resolved transient absorption spectroscopy (TAS). The TAS studies revealed that the introduction of ILs in the developed PC/CNT composites leads to the formation of biexcitons when compared to the IL-free composites. Moreover, no direct correlation between S and exciton lifetimes was found for the IL-containing composites. Instead, the exciton lifetime decreases while the conductivity seems to increase due to the availability of more free-charge carriers in the polymer matrix.

Tailored pretreatment of serum samples and biomarker extraction afforded by ionic liquids as constituents of aqueous biphasic systems

Prostate cancer serum biomarkers, such as the U.S. Food and Drug Administration (FDA)-approved prostate specific antigen (PSA), are valuable markers of diagnosis, response to treatment and disease progression. Despite the expected benefits of using PSA to better manage the mortality and morbidity associated to prostate cancer, sample complexity and interference within analysis make its quantification in serum a high-cost and strenuous assignment. Here, we make use of the simple preparation, water-rich environment, and selectivity of aqueous biphasic systems (ABS) to develop alternative serum pretreatment strategies. A set of ammonium- and phosphonium-based ionic liquids (ILs) were used as either main phase-forming agents in IL-salt ABS or as adjuvants in polymer-salt ABS, allowing to explore the IL designer solvent nature and versatile role in ABS formation and performance. Serum pretreatment efficiency was evaluated by the capacity of each ABS to simultaneously deplete high abundance serum proteins (immunoglobulin G, IgG, and human serum albumin, HSA) at the systems’ interphase (thus, generating a three-phase partitioning system – ABS-TPP) and extract PSA to a single ABS phase. Regardless of the ABS typology under appraisal (IL-salt or polymer-salt-IL), the proper design of the IL structure is critical for both the ability to deplete high abundance serum proteins and extract PSA. The results demonstrate that, in addition to the proper choice of the ABS typology, a careful adjustment of the IL hydrophobicity is key to achieve the simultaneous depletion of high-abundance proteins and complete PSA extraction in a single step, creating new approaches for PSA analysis and its application in diagnosis/prognosis.

Wetting behaviour of phosphonium-based halogen-free ionic liquids as lubricant additives on various metal surfaces

Metalworking fluids (MWFs) have high demand in manufacturing industries as they reduce the friction and wear of the surfaces in contact and improve the life of the system. Traditionally, petroleum-based MWFs are used, which may cause major health risks to machine operators and have a detrimental effect on the environment. Ionic liquids (ILs) have commenced as a potential alternative to conventional MWFs due to their unique properties such as low or negligible volatility, high polarity, high thermal stability, and better spreadability. However, the majority of the investigated ILs contain halogen-based anions, which are moisture sensitive and have the potential to generate hazardous halogen acids. These acids are harmful to the environment and have the potential to corrode working surfaces. The ILs properties such as viscosity, and wettability play an important role in the tribological performance of sliding pairs. This research work examines the wetting behaviour of one phosphonium-based halogen-free ILs and two halogen-based ILs as an additive to canola oil on mild steel, stainless steel, aluminum and titanium alloys. For comparison, the wetting behaviour of pure canola oil on different alloys was also examined using a contact angle goniometer. The finding suggests that wetting behaviour of phosphonium-based halogen-free ILs blended with canola oil shows a low contact angle for all different alloys due to the presence of long alkyl chain as compared to other MWFs. Furthermore, the wetting behaviour of the same MWFs varies for different metal surfaces due to the intermolecular interaction between ions of ILs and the surface adsorption properties of different metals. Presumably, this study shows the potential of wetting behaviour/spreadability of phosphonium-based halogen-free ILs as lubricant additives on various metal surfaces. The phosphonium-based halogen-free ILs blended with canola oil shows contact angle in the range of 23° to 28° at the stabilizing time of 1000 ms on the surface polished with 320G abrasive sheet for all materials, whereas, with canola oil, the contact angle varies in between 28° to 38° the with same parametric conditions. Overall, 27% and 22% improvements in spreadability were observed using phosphonium-based halogen-free ILs blended in canola oil on the surface of mild steel and titanium, respectively for polished surfaces with 320G abrasive sheet after stabilizing time of 1000 ms. At the same parameters, for steel and aluminum, only 7% and 8% improvements in spreadability were observed, respectively.

Phosphonium-based ionic liquids as grease additives in rolling bearing tests

Two phosphonium-derived ionic liquids: trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate (IL1) and trihexyltetradecylphosphonium tricyanomethanide (IL2) were used as additives in lithium complex- (G1) and anhydrous calcium-based (G2) greases at 5 wt%. Friction torque and wear tests were performed using a modified four-ball machine for testing rolling bearings in order to determine the friction and wear reducing properties of these grease samples in a real component. The IL2 improved the friction reduction performance of both greases, especially G1. Both ILs improved the antiwear behaviour of grease G2. Grease G2 showed higher oxidation and thermal ageing levels than G1, but the addition of the ILs, IL2 in particular, improved this issue.

The surface chemistry of ionic liquid-treated CsPbBr3 quantum dots.

The power conversion efficiencies of lead halide perovskite thin film solar cells have surged in the short time since their inception. Compounds, such as ionic liquids (ILs), have been explored as chemical additives and interface modifiers in perovskite solar cells, contributing to the rapid increase in cell efficiencies. However, due to the small surface area-to-volume ratio of the large grained polycrystalline halide perovskite films, an atomistic understanding of the interaction between ILs and perovskite surfaces is limited. Here, we use quantum dots (QDs) to study the coordinative surface interaction between phosphonium-based ILs and CsPbBr3. When native oleylammonium oleate ligands are exchanged off the QD surface with the phosphonium cation as well as the IL anion, a threefold increase in photoluminescent quantum yield of as-synthesized QDs is observed. The CsPbBr3 QD structure, shape, and size remain unchanged after ligand exchange, indicating only a surface ligand interaction at approximately equimolar additions of the IL. Increased concentrations of the IL lead to a disadvantageous phase change and a concomitant decrease in photoluminescent quantum yields. Valuable information regarding the coordinative interaction between certain ILs and lead halide perovskites has been elucidated and can be used for informed pairing of beneficial combinations of IL cations and anions.