Aqueous electrolyte presents in batteries have high ionic conductivity. They are economic, non-flammable and offer high energy density. However, restricted thermodynamic electrochemical stable ...potential window of water and its spilling suppresses the use of these batteries. To address these problems, development of a polymer-based electrolyte system is an upcoming area of research. Even, the uses of sodium salts in battery electrolytes are gaining importance over lithium salts due to their abundance and economic feasibility. The present study examines the self-aggregation of star block copolymer Tetronic® 1107 in aqueous medium in the presence of sodium salts viz. sodium chloride, sodium fluoride, sodium nitrate, sodium hexafluoro phosphate and disodium hydrogen phosphate with different anions by cloud point (CP), gelation, dynamic light scattering (DLS) and small angle neutron scattering (SANS). Conductivity and DC polarization measurements are also performed for polymeric systems in the absence and also in the presence of these salts. The gelation behaviour of the block copolymer to reduce leakage problems and proper ionic conductivity of it in the presence of sodium salts make the system a credible choice as a polymer gel electrolyte (PGE).
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•A systematic study defining the role of Tetronics® 1107 as a PGE component is reported.•Phase and gelation behaviour of block copolymer under the influence of sodium salts are discussed.•DLS and SANS are utilised for identifying shape and size of the micelles.•Ionic conductivity, transport number measurements are performed for polymer in the presence and absence of salts.•Decrease of CP and an enhanced micellar size and conductivity is observed in the presence of salts.
•The size- and stress-dependent dislocation-DLs interactions are investigated by MS and MD, with the emphasis focused on its kinetic effect.•The dislocation tends to fully absorb/transform small DLs ...but only to partially absorb/transform large ones.•When the dislocation is accelerated to subsonic speed, abnormal “pull-forward” configurations can be formed after it bypasses the small DLs.•The kinetic effect decreases the CRSS of dislocation bypassing DLs evidently.•Both amended DBH and BKS hardening models are proposed to consider the above kinetic effect.
In this paper, the interaction between an edge dislocation and irradiation sessile self-interstitial atom (SIA) type dislocation loops (DLs) is studied by atomistic simulations in BCC Ta at 0 and 300 K. Both molecular dynamics (MD) and statics (MS) simulations are performed to highlight the dislocation kinetic effect (or dynamic effect) on the critical resolved shear stress (CRSS) for dislocation bypassing the DLs and on the dislocation-SIA DLs interaction mechanisms. The simulation results show that the dislocation-DLs interaction mechanisms are two-fold. When the DL size is lower than a critical value, the moving edge dislocation tends to completely absorb the DLs or fully transform the original DLs into other-type ones. However, when the DL size is higher than the critical value, the moving dislocation tends to absorb or transform the DLs partially or even marginally. Moreover, with increasing applied shear stress, the high-speed dislocation has no sufficient time to absorb SIAs from DLs, which also changes the dislocation-DLs interaction process remarkably. When the dislocation is accelerated to subsonic, an abnormal “pull forward” dislocation configuration may present upon the dislocation bypasses a small DL. More importantly, with the kinetic effect considered, the CRSS for dislocation overcoming the barriers of DLs decreases significantly for the dislocation-DLs interaction mechanisms. In order to appropriately describe the kinetic effect on the CRSS, amended dispersed barrier hardening (DBH) and Bacon-Kocks-Scattergood (BKS) hardening models for the latter dislocation-DLs interaction mechanism are proposed.
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•Nano emulsions of neem and citronella oils developed and standardized.•Nano emulsions of neem and citronella oils mixture exhibited promising antifungal activity against phytopathogenic ...fungi.•Morphology, stability and particle size of nano emulsions were determined.•Nano emulsions could be useful to control of plant diseases caused by R. solani and S. rolfsii.
Biopesticides are considered to be safe, target specific, biodegradable and eco-friendly. These, especially Azadirachta indica A. Juss. (neem) based biopesticides, are mainly used as emulsified concentrate (EC). There is growing interest in nano emulsions based on phytochemical mixtures due to their better efficacy compared to conventional biopesticides. A. indica seed oil and Cymbopogon nardus (L.) Rendle (Citronella) oil are known to have pest control properties. However, their utilization is often restricted due to relatively low water solubility. This drawback can be overcome by encapsulating oils in oil-in-water (O/W) emulsions or nano emulsions using low or high energy methods. In this study, various nano emulsions of crude neem and citronella oils with surfactants were developed and characterised by Dynamic Light Scattering (DLS) and Transmission Electron Microscope (TEM). Composition of various ingredients of nano emulsions was standardised. TEM study showed the spherical shape of neem and citronella oil nano emulsions. The average size of droplets of neem nano emulsion (NNE) with different percentage of citronella oil ranged from 11.23±3.86nm to 17.80±4.52nm while that of citronella nano emulsion (CNE) with different percentage of neem oil ranged from 8.12±2.80nm to 12.04±3.74nm. It was found that increase in surfactant ratio to neem oil or citronella oil decreases the size of droplets in nano emulsions. Further, in vitro antifungal study of against Rhizoctonia solani and Sclerotium rolfsii was carried out by poisoned food technique. Results showed that neem nano emulsion 10 (NNE10) and citronella nano emulsion 10 (CNE10) were most active against R. solani (ED50 13.67mgL−1 and 25.64mgL−1) and S. rolfsii (ED50 14.71mgL−1 and 20.88mgL−1). The standardization of the composition and development of citronella essential oil and neem oil based nano emulsions and their antifungal activity against these two fungi has been reported for the first time.
Light scattering methods permit the determination of molar mass and hydrodynamic radius for a protein from first principles. They are, therefore, particularly useful for the biophysical ...characterization of any protein. Molar mass and hydrodynamic radius determinations may be used to demonstrate that the protein of interest multimerizes. In the endomembrane system, reversible and regulated assembly and multimerization of proteins is critical for building coats required for vesicle budding, for the function of membrane remodeling machines, for fission and fusion and for assembling and disassembling trafficking intermediates. Light scattering methods have therefore significantly contributed to the understanding of the underlying trafficking processes. Herein, we describe methods to express and purify the recombinant fungal SNX-BAR Mvp1, a membrane remodeling protein required for retrograde trafficking at the endosome. Using Mvp1 as an example, we provide protocols for determining its molar mass and hydrodynamic radius by multiangle static light scattering and dynamic light scattering, respectively. These methods can be applied directly to the study of other membrane trafficking proteins, yielding a wealth of biophysical and biochemical information.
•Submicron heterogeneities spontaneously form in aqueous solutions of sugars.•Submicron heterogeneities are destroyed in glass capillaries.•This factor may be an important mechanism of microfluidics.
...In this paper, we study submicron heterogeneities (SMH) that spontaneously form in aqueous solutions of sugars: glucose, fructose and sucrose, with a concentration of 0.5 mol%. These solutions were passed through glass capillaries with a diameter of about 6 and 13 µm, which led to a decrease in the concentration of SMH without significantly changing their size. For capillaries of smaller diameter, this effect is more pronounced. The decrease in the concentration of SMH is not associated with their mechanical destruction or adsorption on the surface of capillaries. This phenomenon is explained by the destruction of SMH as a result of their interaction with the hydrophilic surface of the capillary. The fundamental differences between the presence of SMH in microfluidic conditions and bulk reservoirs are discussed. This phenomenon should be taken into account in microfluidics.
The early stage of aggregation of titanium oxide (TiO2) nanoparticles was investigated in the presence of extracellular polymeric substance (EPS) constituents and common monovalent and divalent ...electrolytes through time-resolved dynamic light scattering (DLS). The hydrodynamic diameter was measured and the subsequent aggregation kinetics and attachment efficiencies were calculated across a range of 1–500 mM NaCl and 0.05–40 mM CaCl2 solutions. TiO2 particles were significantly aggregated in the tested range of monovalent and divalent electrolyte concentrations. The aggregation behavior of TiO2 particles in electrolyte solutions was in excellent agreement with the predictions based on Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Divalent electrolytes were more efficient in destabilizing TiO2 particles, as indicated by the considerably lower critical coagulation concentrations (CCC) (1.3 mM CaCl2 vs 11 mM NaCl). The addition of EPS to the NaCl and low concentration CaCl2 (0.05–10 mM) solutions resulted in a dramatic decrease in the aggregation rate and an increase in the CCC values. For solutions of 11 mM NaCl (the CCC values of TiO2 in the absence of EPS) and above, the resulting attachment efficiency was less than one, suggesting that the adsorbed EPS on the TiO2 nanoparticles led to steric repulsion, which effectively stabilized the nanoparticle suspension. At high CaCl2 concentrations (10–40 mM), however, the presence of EPS increased the aggregation rate. This is attributed to the aggregation of the dissolved extracellular polymeric macromolecules via intermolecular bridging, which in turn linked the TiO2 nanoparticles and aggregates together, resulting in enhanced aggregate growth. These results have important implications for assessing the fate and transport of TiO2 nanomaterials released in aquatic environments.
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•TiO2 particles were significantly aggregated in the tested electrolyte solutions.•Ca2+ ions were more efficient in destabilizing TiO2 NP than Na+ ions.•The aggregation of TiO2 NP in solutions was agreement with DLVO theory.•In NaCl and low CaCl2, EPS stabilized the NP suspension due to steric repulsion.•At high CaCl2, EPS increased aggregation rate of NPs by intermolecular bridging.
The photo differential scanning calorimetry (photo-DSC) is an appropriate method to characterize photopolymers used in additive manufacturing (AM). Important process parameters such as optimal ...ultraviolet (UV) exposure time and reaction heat can be attained by this method. However, achieving reliable and meaningful results from photo-DSC experiments requires careful sample preparation, i.e. the selection of a suitable sample shape, sample mass and sample holder (crucible). The sample shapes drop and spread with 1.0 mg and 2.8 mg sample masses were investigated in this study. Three different times from sample preparation until the start of the measurement (0, 4 and 7 h) were tested, in order to investigate different surface effects such as oxygen-diffusion, prior UV-curing through ambient radiation and evaporation of volatile components. While the 1.0 mg spread sample shape offers the thinnest film thickness (40 μm) and thus the closest comparability to high resolution print jobs, the 2.8 mg drop shape offers a more robust sample preparation with minimized surface effects. To further reduce time-dependent surface effects, this study shows how a preexisting test protocol was shortened from 42 min to 24 min without losing measuring accuracy. Furthermore, to reduce evaporation, different covers were placed on different crucibles, which were tested over time in the device’s automated sample changer (ASC) that enables automated and consecutive measurements. The combination of a cold pressed 85 μL crucible covered with a 300 μL Al2O3 crucible, which is removed shortly before the actual measurement, provides the best sample preparation for the ASC since mass loss remains below 1% for up to 10 h. Finally, two two-part resin systems, namely a methacrylate-urethane and an acrylate-epoxy based resin that are used in Digital Light Synthesis (DLS) are characterized part by part as well as in mixed state. Together with the investigation of different temperatures and atmospheres, it was possible to identify not only the part with the photoinitiator and the type of system (radical or cationic), but also a difference between methacrylates and acrylates with the aid of the photo-DSC method.
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•The 1.0 mg spread sample shape has shortest times to peak.•The 2.8 mg drop sample shape is more robust towards time-dependent surface effects.•EPX 82 follows a radical not a cationic or hybrid reaction system.•The reaction heat of EPX 82 is almost twice as much compared to RPU 70.•Sample preparation for reduced mass loss with the ASC of the DSC is presented.
•A strong emitting luminophore, CNH showing AIEE behavior has been synthesized.•The aggregate formation at higher water content is confirmed by AFM and DLS methods•CNH probe is utilized for solvent ...dependent colorimetric detection of Cu2+ and F−.•CNH interacts with Cu2+ and F− in 1:1 stoichiometry.•The color change of CNH probe with Cu2+ is due to ligand to metal charge transfer.
A 3-acetyl coumarin appended probe 3-((Z)-1-((E)-((2-hydroxynaphthalen-1-yl) methylene) hydrazono)ethyl)-2H-chromen-2-one (CNH) has been successfully synthesized and characterized by different spectroscopic tools via IR, 1H & 13C NMR and HRMS. The probe displays solvent dependent colorimetric detection of Cu2+ and F− ions in THF and DMF media, respectively. CNH interacts with Cu2+ in 1:1 stoichiometry with limit of detection 1.4 × 10−6 M. The color change of probe with addition of Cu2+ ions is due to ligand to metal charge transfer (LMCT) as suggested by UV–Vis spectra and DFT studies. Furthermore, CNH interacts with F− in 1:1 stoichiometry with detection limit 1.32 × 10−6 M by proton transfer mechanism from O-H to F−, which enhances the electron density on CNH molecule as suggested by UV–Vis, NMR titration and DFT studies. In addition to intriguing colorimetric sensing applications, CNH displays remarkable aggregation induced emission (AIE) property in DMF/water binary mixture. The probe is almost non-fluorescent in solution but becomes strongly emissive in aggregate/solid state. The formation of aggregates at higher water content is confirmed by atomic force microscopy (AFM) and dynamic light scattering (DLS) studies in mixed water media. DLS measurements suggest the increase in average particle size from 100 nm to 299 nm upon increasing water fractions from (fw = 10%) to (fw = 90%). AFM studies also provide additional information about the aggregates at higher water fraction. In the range of 100–500 nm, the topography of surface shows that the aggregates are spherical in shape (fw = 90%).
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Nanomaterials can be produced by using nontoxic biological compounds that are both eco-friendly and economically viable. Temperature dependent ecological synthesis of ZnO nanoparticles was carried ...out with leaf extract of Ocimum sanctum. An electron microscope study confirmed that a temperature of 400 oC was optimal for the formation of ZnO nanoparticles generated by biosynthesizing ZnO nanoparticles. The normal crystalline size of biosynthesized ZnO nanoparticles calculated via XRD analysis are found to be 18, 12 and 17 nm for 300 - 500 oC, respectively. The direct optical band gap energy deducted from Tauc approximation range to be 3.32-3.20 eV. In SEM analysis, depending on the temperature of the synthesis conditions, different ZnO morphologies are also found. Functional groups analysis confirmed the incidence of carboxyl and amide groups in the O. sanctum leaf extract. The ZnO nanoparticles analysed at room temperature using photoluminescence, a broad visible band is observed around 382 nm for all samples. Furthermore, this study determines that the synthesized ZnO nanoparticles provide antimicrobial efficacy against clinical strains of Bacillus subtilis and Staphylococcus aureus, as well as against standard strains of Escherichia coli. Several fields, including cosmetics and pharmaceuticals, can benefit from biosynthesized nanoparticles.
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Hypothesis: Common amphiphilic drug molecules often have a more rigid nonpolar part than conventional surfactants. The rigidity is expected to influence the self-assembling properties ...and possibly give rise to aggregation patterns different from that of regular surfactants.
Experiments: We have investigated self-assembling properties of the hydrochloride salts of adiphenine (ADP), pavatrine (PVT), and amitriptyline (AMT) at concentrations up to 50 wt% using small-angle x-ray scattering, dynamic light scattering, cryo-transmission electron microscopy, and surface tension measurements.
Findings: All drugs form small micelles of oblate spheroidal shape at concentrations above the critical micelle concentrations (CMC). The micelles grow weakly in size up to about 20 wt%, where the aggregation number reaches a maximum followed by a slight decrease in size at higher drug concentrations. We observe a correlation between the decrease in micelle size at high concentrations and an increasing charge of the micelles, as the degree of ionization increases with increasing drug concentration and decreasing pH. In contrast to what has previously been reported, the aggregation behavior of all studied drugs resembles the closed association behavior of conventional surfactants with a short aliphatic chain as hydrophobic tail group i.e. the micelles are always small in size and lack a second CMC. CMC values were determined with surface tension measurements, including also lidocaine hydrochloride (LDC) and chlorpromazine hydrochloride (CHL).
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