Addition Of Organic Salts Research Articles

Exploring the mechanism of gallium nitride surface quality enhancement by green organic additives in chemical mechanical polishing

This study presents a novel approach using colloidal silica and organic salt additives for ultra-precision processing of GaN films. The chemical mechanical polishing (CMP) process significantly reduced the surface roughness (Sq) to a minimum of 0.63 nm, while improving the material removal rate by 60 % (from 70 nm/h to 112 nm/h). Contact angle experiments confirmed enhanced slurry wettability due to the organic salts, reducing the contact angle between the polishing slurry and GaN surface from 20° to less than 10°. Additionally, X-ray photoelectron spectroscopy (XPS) and quantum chemical calculations explained the inhibition of the oxide layer through adsorption energy. These insights contribute to optimizing GaN CMP processes for fabricating high-performance GaN devices.

Exploration of Solution-Processed Bi/Sb Solar Cells by Automated Robotic Experiments Equipped with Microwave Conductivity.

Solution-processed inorganic solar cells with less toxic and earth-abundant elements are emerging as viable alternatives to high-performance lead-halide perovskite solar cells. However, the wide range of elements and process parameters impede the rapid exploration of vast chemical spaces. Here, we developed an automated robot-embedded measurement system that performs photoabsorption spectroscopy, optical microscopy, and white-light flash time-resolved microwave conductivity (TRMC). We tested 576 films of quaternary element-blended wide-bandgap Cs-Bi-Sb-I semiconductors with various compositions, organic salt additives (MACl, FACl, MAI, and FAI, where MA and FA represent methylammonium and formamidinium, respectively), and thermal annealing temperatures. Among them, we found that the maximum power conversion efficiency (PCE) was 2.36%, which is significantly higher than the PCE of 0.68% for a reference film without an additive. Machine learning (ML) and statistical analyses revealed significant features and their relationships with TRMC transients, thereby demonstrating the advantages of combining ML and automated experiments for the high-throughput exploration of photovoltaic materials.

(Invited) Using Ionic Liquid and Organic Salt Additives to Modify CO2 Electroreduction Selectivity on Copper

Copper is the only metal that can be used as an electrocatalyst to produce hydrocarbons and alcohols in CO2 electroreduction. Controlling selectivity to specific products is very challenging, limiting the viability of CO2 electroreduction on copper to synthesize fuels or chemicals. To obtain products that contain hydrogen, aqueous electrolytes are generally necessary, which also leads to competition with hydrogen evolution reaction (HER). By using ionic additives such as organic salts and ionic liquids, the water and CO2 concentrations at the interface during CO2 electroreduction can be modified. By changing the species at the electrode interface, the product selectivity can be modified. We have found when using dilute concentrations of additives that the anion has more influence on product selectivity. For example, when 10 mM of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTF2] or 10 mM of Na[NTf2] is used in 0.1M KHO3, the product selectivities are very similar, promoting formate formation. When 1-butyl-3-methylimidazolium dicyanamide [BMIM][DCA] or 10 mM of Na[DCA] is used in 0.1M KHO3, CO2 electroreduction is substantially suppressed and HER is promoted. The hydrophobic and CO2-phillic [NTf2] likely limits the water available at the surface while increasing the concentration of CO2. The hydrophilic and CO2-phobic [DCA] likely increases the water available at the surface and diminishes the concentration of CO2 available for reaction.

Improving the Performance of Supported Ionic Liquid Phase Catalysts for the Ultra-Low-Temperature Water Gas Shift Reaction Using Organic Salt Additives.

The water gas shift reaction (WGSR) is catalyzed by supported ionic liquid phase (SILP) systems containing homogeneous Ru complexes dissolved in ionic liquids (ILs). These systems work at very low temperatures, that is, between 120 and 160 °C, as compared to >200 °C in the conventional process. To improve the performance of this ultra-low-temperature catalysis, we investigated the influence of various additives on the catalytic activity of these SILP systems. In particular, the application of methylene blue (MB) as an additive doubled the activity. Infrared spectroscopy measurements combined with density functional theory (DFT) calculations excluded a coordinative interaction of MB with the Ru complex. In contrast, state-of-the-art theoretical calculations elucidated the catalytic effect of the additives by non-covalent interactions. In particular, the additives can significantly lower the barrier of the rate-determining step of the reaction mechanism via formation of hydrogen bonds. The theoretical predictions, thereby, showed excellent agreement with the increase of experimental activity upon variation of the hydrogen bonding moieties in the additives investigated.

Cinchona‐alkaloid‐based zwitterionic chiral stationary phases as potential tools for high‐performance liquid chromatographic enantioseparation of cationic compounds of pharmaceutical relevance

Enantiomers of cationic compounds of pharmaceutical relevance, namely tetrahydro-ß-carboline and 1,2,3,4-tetrahydroisoquinoline analogs, were separated by high-performance liquid chromatography. Separations were performed on Cinchona-alkaloid-based zwitterionic ion exchanger type chiral stationary phases applied as cation exchangers using mixtures of methanol and acetonitrile or tetrahydrofuran as bulk solvent components containing triethylammonium acetate or ammonium acetate as organic salt additives. On the zwitterionic ZWIX(+) and ZWIX(-) columns investigated, retention and enantioseparation of the studied basic analytes were influenced by the nature and concentration of the organic components of the mobile phase. The effect of organic salt additives on the retention behavior of the studied analytes can be described by the stoichiometric displacement model related to the counterion concentration. Investigations on the structure-retention relationships were performed applying different mobile phase systems for the two types of cationic analytes. For the thermodynamic characterization, parameters such as changes in standard enthalpy (Δ(ΔH°)), entropy (Δ(ΔS°)), and free energy (Δ(ΔG°)) were calculated on the basis of van't Hoff plots derived from the ln α versus 1/T curves. In most cases, enthalpy-driven enantioseparations were observed, with a consistent dependence of the calculated thermodynamic parameters on the mobile phase composition. Elution sequences of the studied compounds were determined in all cases.

The rheological behavior of organic salt/Gemini surfactant mixed systems: Effect of isomerization of additives

The effect of isomerization of organic salts (2-hydroxybenzoic acid monosodium salt (o-ph-ONa), 3-hydroxybenzoic acid monosodium salt (m-ph-ONa), and 4-hydroxybenzoic acid monosodium salt (p-ph-ONa)) on the formation and properties of wormlike micelles in 2-hydroxyl-propanediyl-α,ω-bis(dimethyldodecylammonium bromide) (abbreviated as 12-3(OH)-12) aqueous solutions were investigated using rheological methods, surface tension, and 1H–1H 2D NOESY NMR. The results indicate that the addition of organic salts can promote the formation of wormlike micelles. However, the effect of o-ph-ONa is the strongest and that of p-ph-ONa is the weakest. These are attributed to the occupying area of molecules. The hydroxyl and carboxylate groups in o-ph-ONa molecules are on the micelle interface and can interact with the hydroxyl group in the spacer of 12-3(OH)-12 by electrostatic interaction and/or hydrogen bonding associations, inducing a closer micelle arrangement than the other two kinds of salts so that the occupying area of molecules may be the smallest. The hydroxyl group in m-ph-ONa is located at the meta-position of carboxylate groups, which widens the gap of surfactant molecules and increases the occupying area of molecules. The whole p-ph-ONa molecule is located within the micelle interior and shows low viscosity owing to the high molecular occupying area.

Enantioselective resolution of biologically active dipeptide analogs by high-performance liquid chromatography applying Cinchona alkaloid-based ion-exchanger chiral stationary phases

Sixteen pairs of enantiomeric dipeptides were separated on four chiral ion-exchanger-type stationary phases based on Cinchona alkaloids. Anion-exchangers (QN-AX, QD-AX) and zwitterionic phases [ZWIX(+)™ and ZWIX(−)™] were studied in a comparative manner. The effects of the nature and concentrations of the mobile phase solvent components and organic salt additives on analyte retention and enantioseparation were systematically studied in order to get a deeper insight into the enantiorecognition mechanism. Moreover, experiments were performed in the temperature range 10–50 °C to calculate thermodynamic parameters like changes in standard enthalpy, Δ(ΔH°), entropy, Δ(ΔS°), and free energy, Δ(ΔG°) on the basis of van't Hoff plots derived from the ln α vs. 1/T curves. Elution sequences of the dipeptides were determined in all cases and, with a few exceptions, they were found to be opposite on the pseudoenantiomeric stationary phases as of QN-AX/QD-AX and of ZWIX(+) and ZWIX(−). The stereoselective retention mechanism is based on electrostatically driven intermolecular interactions supported by additional interaction increments mainly determined by the absolute configuration of the chiral C8 and C9 atoms of the quinine and quinidine moieties.

Liquid chromatographic resolution of natural and racemic Cinchona alkaloid analogues using strong cation- and zwitterion ion-exchange type stationary phases. Qualitative evaluation of stationary phase characteristics and mobile phase effects on stereoselectivity and retention

Liquid chromatographic (LC) and subcritical fluid chromatographic (SFC) resolution of the basic natural and synthetic Cinchona alkaloid analogues has been studied. Focus has been placed on the employment of four enantiomerically structured chiral strong cation-exchangers and four chiral diastereoisomeric Cinchona alkaloid and cyclohexyl aminosulfonic acid-based zwitterionic ion-exchangers. Except for the novel, recently synthesized racemic quinine the other investigated pairs of basic analytes are diastereomeric, but often called “pseudoenantiomeric” compounds of quinine and quinidine, cinchonidine and cinchonine, 9‑epi‑quinine and 9‑epi‑quinidine. As expected, the elution order of the resolved racemic quinine was reversed for all the eight investigated enantiomeric and (pseudo)enantiomeric pairs of chiral stationary phases, whereas this was not necessarily the case for the diastereomeric pairs of the Cinchona alkaloid related analytes. Varying the type and composition of the protic (methanol) and non-protic (acetonitrile) but polar bulk solvents in combination with organic salt additives in the mobile phase the overall retention and stereoselectivity characteristics could be triggered, leading to well performing LC and SFC systems.Thus the retention behavior of the basic analytes on both the chiral cation-exchangers and the diastereomeric zwitterionic ion-exchangers, used as cation-exchangers, could be described by the stoichiometric displacement model related to the counter-ion effect of the mobile phase additives. In addition, it became obvious that the non-protic acetonitrile compared to methanol as bulk solvent lead to a significant increase in retention, which can be associated with an increased electrostatic interaction of the charged sites due to a smaller solvation shell of the solvated cationic and anionic species. Based on the chromatographic results of the systematically selected chiral analytes and stationary phases attempts were undertaken to interpret qualitatively the observed stereoselectivity phenomena.

Diffusiophoresis as ruling effect: Influence of organic salts on thermodiffusion of iron oxide nanoparticles

Colloidal particles, including ferrofluidic nanoparticles (NP), move in a temperature gradient due to thermodiffusion. Organic salts, which are often added to disperse the NP in aqueous solution, also move in the temperature gradient. This can have a strong influence on the behavior of the NP, which not only respond to the temperature gradient but also to the concentration gradient of the dispersive salt, an effect termed diffusiophoresis. In this work we present experimental results on thermodiffusion of iron oxide nanoparticles dispersed in aqueous solutions of organic hydroxides, which illustrate the possibility to manipulate the thermodiffusion of NP through the addition of organic salts. Our experiments investigate the temperature dependence of the particles' Soret coefficient, a recurring question on thermodiffusion of water-dispersed particles. Existing theoretical approaches are compared and we relate the Soret coefficient of the NP with two main physical parameters ruling particle motion: the NP's electrostatic potential and the Soret coefficient of the dispersing ions. These parameters are also experimentally determined. At the order of magnitude of the NP's Soret coefficient good agreement between experiments and theory is achieved by including the experimental data on the Soret coefficient of the dispersing ions and therefore the NP's displacement due to the ion concentration gradient. Taking into account the temperature dependence of such previously unknown parameters is a relevant step to describe the temperature dependence of the NP's Soret coefficient.

The effect of organic salts on the browning of dried squid products processed by air-drying

To control discoloration of dried Japanese common squid (Todarodes pacificus) product, influence of 0–1% organic salts, including sodium gluconate (Na-gluconate), sodium citrate (Na-citrate), sodium phytate (Na-phytate), sodium benzoate (Na-benzoate) and sodium tartrate (Na-tartrate), on Maillard browning in the squid meat during air-drying was investigated. Changes in surface color of the dried squid were mitigated by the addition of organic salts. Organic salts also showed inhibitory effects on autolysis and generation of free amino acids (FAAs), especially arginine, in both the dried squid meat and the model solution. Moreover, Maillard reaction degree of the dried squid was decreased by using organic salts. The addition of 1% Na-citrate or 1% Na-phytate well suppressed the browning of the dried squid (p < 0.05). The results indicated that organic salts having strong chelating ability, including Na-citrate and Na-phytate, can prevent the browning of the dried squid product by inhibiting the generation of FAAs.

STUDIES ON THE EFFECT OF SOME SALT ADDITIVES ON THE SKIN AND COAT CHARACTERISTICS OF SHEEP IN HEDERBA VALLEY RANGES

Thirty Aboudeleik ewes aged 3-5 years with an average body weight of 37.5±3.75 kg were used in the study at RasHederbaValley region (Shalateen Research Station, DesertResearchCenter). The present work was designed to evaluate the effects of organic and inorganic salt additives on some histological responses of skin and wool follicles and coat changes of Aboudeleik ewes. Sheep skin consists mainly of epidermis and dermis. The epidermis composed of stratified squamous keratinized epithelium. The dermis consists of connective tissue which is divided into an upper papillary layer and a lower reticular layer.The experimental results revealed that the addition of the two forms of salt additives to the sheep nutrition showed variable changes in the thickness of all skin layers of treated animals than the control group. The skin thickness and the papillare layer were thinner in sheep fed on organic salt additives while the reticular layer increased significantly by the two forms of salt additives. Values of all primary and secondary wool follicle dimensions increased by the use of the two forms of salt additives than the control group. The external and internal diameters of the primary follicles increased significantly in the treatment groups. In case of secondary follicles, the external diameter and the wall thickness were affected significantly in the inorganic group than those of the other two groups. The diameter of fibres produced from the primary follicles and the medulla thickness increased significantly by the two forms of salt additives than those of control group with no significant differences between them. Whereas organic salt additives affected significantly the diameter of the fibres produced by the secondary follicle. The coat fibres of Aboudeleik sheep were of bimodal structure usually consists of outer and under coats. Animals have supplemented diets with the two forms of salt additives recorded the highest percentage of fibres from type A and also the under coat percentage whereas inorganic group represented the highest percentage of type B. The greatest percentage of type C was found in the animals supplemented with organic salt additives. The fibres length and number of crimps/centimeter in Aboudeleik sheep was affected by the use of the two forms of salt additives. Sheep had inorganic salt additives recorded a significant increase in the length of type A than those of the other two groups and of type B only with the control group. It could be concluded that the supplementation of sheep diets with salt additives is a useful method in challenging the unbalanced salt conditions found in the rangeland of desert regions which affects the livestock development throughout the production and performance of animals.

Air-stable n-type tellurium nanowires coordinated by large organic salts

Chemically-synthesized semiconductor nanostructures have the potentials for the exploration of unprecedented electronic and thermoelectric properties. Such materials possess the surface area much larger than their bulk forms, resulting that surface chemical functionalization may alter electronic properties. Here we report on the modulation of majority carriers in semiconductor nanowires by the addition of organic salts. The p-type nanowires were successfully converted to n-type forms to which large cations such as onium ions and metal-crown ether complexes are coordinated.

Preparation of self-clustering highly oriented nanofibers by needleless electrospinning methods

Polyacrylonitrile (PAN) oriented nanofibers were produced by homemade needleless electrospinning device. Spiral coils were adopted to replace the traditional spinning needles in this equipment. The tracks of multi-jets were controlled by adjusting the microcurrent during the eletrospinning process. The microcurrent value and the motion track of the spinning jet during the spinning process were observed, the fiber morphology and the mechanical properties of fiber membranes were measured. The results revealed that the average diameters of the electrospun fibers were increased from 490 nm to 740 nm. with the addition of organic salt. Meanwhile, the self-clustering phenomenon was obviously observed, and the mechanical properties of obtained fibers were also altered, the tensile strength was improved from 3.63 MPa to 23.90 MPa, while the strain decreased from 74.6 % to 27.1 %.

Effect of organic salts on the aggregation behavior of tri-(trimethylsiloxy)silylpropylpyridinium chloride in aqueous solution

In this study, we synthesized the cationic silicone surfactant tri-(trimethylsiloxy)silylpropylpyridinnium chloride (Si4pyrCl). We then systematically investigated the effects of organic salts such as sodium acetate, sodium oxalate, sodium citrate, sodium benzoate, and sodium salicylate on the aggregation behavior of Si4pyrCl in aqueous solution through surface tension and electrical conductivity analyses, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The addition of organic salts promoted surfactant aggregation. The aggregation ability was observed to be in the following order: s sodium salicylate>sodium benzoate>sodium citrate>sodium oxalate>sodium acetate. The measurement of electrical conductivity shows that the micellization of Si4pyrCl in aqueous solution is spontaneous. Several spherical-like aggregates with a diameter of approximately 500nm were observed via TEM. The diameter distribution was determined through DLS. This work will be of great significance for the understanding of cationic silicone surfactants and their applications in industrial production.

Concentration Enhancement of Liquid Phase Exfoliated Graphene with Addition of Organic Salts

Abstract A facile sonochemical route has been proposed in which liquid phase exfoliation of graphite into single and multi-layer graphene is obtained. An organic solvent ortho-dichlorobenzene (ODCB) is used for the graphene exfoliation and the effect of addition of organic salts in ODCB solvent is investigated. The characterization of the as prepared graphene is done using SEM, TEM and UV-Visible spectroscopy. The graphene film was prepared using vacuum filtration method and resistivity measurement was done using Four-Probe method. The application of graphene film in making flexible paper supercapacitor is demonstrated. It is observed that the concentration of graphene synthesized by liquid phase exfoliation method has been found to enhance appreciably with addition of EDTA disodium salt.

The influence of different preservation methods on spoilage bacteria populations inoculated in morcilla de Burgos during anaerobic cold storage

Blood sausage is a widely consumed traditional product that would benefit from an extended shelf life. The two main spoilage bacteria in vacuum-packaged morcilla de Burgos are Weissella viridescens and Leuconostoc mesenteroides. This study examines the way in which three preservation treatments — organic acid salts (OAS), high-pressure processing (HPP) and pasteurization — influence these bacterial populations and their spoilage behaviour. HPP and pasteurization treatments were found to inhibit growth of the inoculated species and delay sensory spoilage of the product. In both treatments, L. mesenteroides was observed to have a longer recovery time; even so, once its growth started, it grew faster than W. viridescens. This longer recovery time might be due to metabolic modification following treatment, which would affect the production of metabolites such as acetic acid and some aldehydes. W. viridescens was the first strain to recover from the two treatments. It preserved its spoilage behaviour and even increased the production of certain compounds such as acetoin or ethanol. The extended product shelf life following HPP and pasteurization treatments might be due to a combination of various factors such as the fall in both microbial populations, as well as the delay in spoilage caused by damage to L. mesenteroides cells, as this strain is the fastest-acting, most intensive spoilage microorganism. It was observed that the addition of organic salts neither diminished nor delayed the growth of the two inoculated species. Nevertheless, the results also indicate that this treatment inhibits the metabolic activity of L. mesenteroides, resulting once again in an extended product shelf life.

Effects of Organic Salt Additives on the Behavior of Dimeric (“Gemini”) Surfactants in Aqueous Solution

The effects of a series of aromatic anions, so-called hydrotropes, on characteristic solution properties of a family of ammonium gemini surfactants with dodecyl chains were explored. The stoichiometric addition of the organic salts to the geminis can result in clear solutions or in phase separation/precipitation, depending on the detailed nature of the added counterions and on the spacer group of the gemini surfactant. Many organic anions induce synergistic effects, strongly reducing the critical micellization concentration (cmc) and the surface tension at the cmc. Furthermore, a number of combinations of organic anions and geminis exhibit thickening of their aqueous solutions. The effects of the added salts are strongly enhanced for the gemini surfactants compared to the monomeric analogue N-dodecyl-N,N,N-trimethylammonium chloride. Even anions such as benzoate may be effective for thickening, and viscoelastic solutions can be obtained with salicylate despite the relatively short alkyl chains.

Electrospun Micro- and Nanofibers for Sustained Delivery of Paclitaxel to Treat C6 Glioma in Vitro

The present study aims to develop electrospun PLGA-based micro- and nanofibers as implants for the sustained delivery of anticancer drug to treat C6 glioma in vitro. PLGA and an anticancer drug--paclitaxel-loaded PLGA micro- and nanofibers were fabricated by electrospinning and the key processing parameters were investigated. The physical and chemical properties of the micro- and nanofibers were characterized by various state-of-the-art techniques, such as scanning electron microscope and field emission scanning electron microscope for morphology, X-ray photoelectron spectroscopy for surface chemistry, gel permeation chromatogram for molecular weight measurements and differential scanning calorimeter for drug physical status. The encapsulation efficiency and in vitro release profile were measured by high performance liquid chromatography. In addition, the cytotoxicity of paclitaxel-loaded PLGA nanofibers was evaluated using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide MTT) assay on C6 glioma cell lines. PLGA fibers with diameters of around several tens nanometers to 10 microm were successfully obtained by electrospinning. Ultrafine fibers of around 30 nm were achieved after addition of organic salts to dilute polymer solution. The encapsulation efficiency for paclitaxel-loaded PLGA micro- and nanofibers was more than 90%. DSC results suggest that the drug was in the solid solution state in the polymeric micro- and nanofibers. In vitro release profiles suggest that paclitaxel sustained release was achieved for more than 60 days. Cytotoxicity test results suggest that IC50 value of paclitaxel-loaded PLGA nanofibers (36 microg/ml, calculated based on the amount of paclitaxel) is comparable to the commercial paclitaxel formulation-Taxol. Electrospun paclitaxel-loaded biodegradable micro- and nanofibers may be promising for the treatment of brain tumour as alternative drug delivery devices.

Electrical properties of σ‐conjugated polymers with additives and their applications in sensors

AbstractThe charge carrier transport in poly[methyl(phenyl)silylene] (PMPSi) proceeds predominantly along the σ‐delocalized Si backbone with participation of interchain hopping and polaron formation. The charge carrier mobility increases with increasing electron affinity of acceptor dopands having zero dipole moments. On the other band, the hole drift mobility is influenced by the dipole moment of the dopand. The electrostatic charge‐dipole interactions cause a broadening of the energy distribution of transport states, which results in a decrease in the charge carrier mobility. An addition of organic salts leads, under the conditions of increased humidity, to an increase in electrical conductivity and capacitance. This is demonstrated on the layers PMPSi/1,5‐dimorpholino‐1,5‐diphenylpentamethinium perchlorate.

Binary and ternary salt gradients in hydrophobic-interaction chromatography of proteins

Hydrophobic-interaction chromatography of mixtures of acidic and basic proteins having a wide range of molecular weights and hydrophobic character was carried out by using binary and ternary salt gradients. Chaotropic and antichaotropic salts as well as organic salts were incorporated in the eluents. The stationary phase consisted of macroporous silica with surface-bound polyether moieties. At constant eluent surface tension, gradient elution with two or three aqueous salt solutions was found to be superior to single-salt gradients in modulating hydrophobic-interaction chromatography retention and selectivity. The effect was attributed to the competitive salt-specific binding to the protein molecule and/or the stationary phase surface. Chaotropic/antichaotropic salt gradient systems exhibited vastly different selectivities upon changing the nature and concentrations of salts in the eluents. In general, the retention of basic proteins increased while that of acidic proteins either decreased or remained unchanged with the use of chaotropic salts. At the same surface tension of the eluent, KSCN and KClO 4 yielded different selectivities. The addition of organic salts, such as tetrabutylammonium bromide was found to be suitable for the separation of proteins having a wide range of isoelectric points.