Presence Of Anionic Surfactants Research Articles

Influence of Sodium Dodecyl Sulfate Anionic Micelles on The Complex Equilibria of Divalent Metal Ions with L-Leucine Amino Acid

The main objectives of the present investigation are the formation analysis of metal-ligand complexes of L-Leucine with divalent calcium, magnesium, and zinc metal ions in various concentrations of sodium dodecyl sulphate (0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 percent w/v). To also look into the impact of the concentration of negatively charged micelles, the parameters that were changed, and the possible chemical species of L-Leucine that interact with the metal ions that were being studied. The experiment was performed using pH meter at 303 K using NaCl to keep your ionic strength stable of 0.16mol dm-3 in the presence of anionic surfactant, sodium dodecyl sulphate (SDS). The determination of the correction factor was conducted via the computer program SCPHD. The computational software MINIQUAD75 is utilized to determine the stability constants of ligand-metal complexes through the analysis of titration data. Based on statistical features such as skewness, 2, kurtosis, and crystallographic R-factor, the best fit to the complicated speciation was selected. The metal ions Ca (II), Mg (II), and Zn (II) formed complexes ML, ML2, and ML2H2 for Ca (II), and ML, ML2, and ML2H for Mg (II) and Zn (II) through the complexation of L-Leucine. In order to validate the accuracy of the final established model, deliberate defects were introduced into the relevant components.

Electrochemical Oxidation of Ranitidine using a Boron-Doped Diamond Electrode in the Presence of Anionic Surfactant: A Comprehensive Investigation

Ranitidine (RAN) is a drug from the histamine H2 receptor antagonist class and is used to prevent excessive production of stomach acid. An electrochemical investigation of the RAN in pharmaceutical preparation and spiked human urine was performed for the using a boron-doped diamond electrode (BDDE). Voltammetric measurements were performed in a pH 11 BR solution supplemented with the anionic surfactant, sodium dodecyl sulfate (SDS). In the proposed method using optimized experimental conditions, linearity was obtained for RAN in the concentration range of 0.8-50.0 μM. The LOD value obtained is 0.22 μM. Good selectivity, accuracy, precision, and acceptable repeatability were also achieved in this proposed electrochemical sensor. Finally, this electrochemical sensor was successfully used for RAN detection in pharmaceutical samples.

Mesoporous pineapple crown-derived activated carbon modified matrix for the detection of carbendazim in the presence of anionic surfactant

Carbon paste electrodes (CPEs) are commonly employed in electroanalysis because of their chemical stability, broad electrochemical window, low capacitive current, ease of fabrication, and surface renewability. Electrocatalysts can easily be embedded into CPEs to make them suitable for a variety of applications. Poor biowaste management presents a significant challenge in the agro-industry and agriculture due to the rapid decomposition of biowaste, driven by its high water content and limited biological stability, which leads to pest attraction and greenhouse gas emissions. Consequently, this green waste can be utilized for the development of electrocatalysts. Activated carbon (AC) has been utilized in progressive electrochemical applications as it exhibits high conductivity and porosity that help to enhance electrocatalytic activity. Herein, pineapple fruit crown (PC) peel-derived AC (PCAC) is utilized as the sensing material for the determination of fungicide, carbendazim (CBM). The synthesized material was characterized using SEM, FT-IR, XRD, EDX, AFM, CV and EIS. Besides, to enhance the surface properties, Sodium dodecyl sulfate (SDS) surfactant is used as a mediator in detecting CBM. The CV and SWV approaches were employed to assess the electrochemical response of the developed electrodes for the CBM determination. Under optimum experimental conditions, the SDS/PCAC/CPE exhibits low DLim and QLim values of 32.0 nM and 128.0 nM with considerable selectivity. Furthermore, the SDS/PCAC/CPE was employed in real-time analysis of CBM in spiked environmental samples, which showed satisfying recovery results. Moreover, the electrode showed good stability over multiple measurements, and these results demonstrate that SDS/PCAC/CPE is a promising sensor for CBM detection.

Oil-in-Water Emulsions Probed Using Fluorescence Multivariate-Curve-Resolution Spectroscopy.

Hydrophobic surfaces in contact with aqueous media are omnipresent in nature. A plethora of key biological and physiological processes occur at the interface of immiscible fluids. Besides its fundamental importance, probing such interfaces is rather challenging, especially when one medium is bathed in the other. Herein, we demonstrate a fluorescence-based method that probes the oil-water interface and interfacial processes through surface dielectric perturbations. The fluorescence response of Nile Red is measured in hexadecane in water nanoemulsions. Three major spectral components appear: two from the bulk liquid media (hexadecane and water) and a distinct band at around 640 nm due to the interfacial component. Such spectra are deconvoluted using the multivariate-curve-resolution algorithm, and interface-correlated fluorescence spectra are attained. The influence of anionic sodium dodecylbenzenesulfonate (SDBS) and cationic cetyltrimethylammonium bromide (CTAB) surfactants on the oil-water interface is elucidated with concentration-dependent measurements. A charge-dependent spectral shift is observed. The interface correlated band at 641 nm for bare hexadecane nanoemulsions red shifts in the presence of anionic surfactants, indicating an apparent dielectric increase. In contrast, the same band gradually blue shifts with increasing cationic surfactant concentration, indicating an apparent interface dielectric decrease. Such a method can be utilized to probe alterations at interfaces beyond the oil/water interface.

Interfacial assembly of polyamide nanofilm membranes regulated by surfactants with different structural characteristics

Polyamide (PA) nanofilm membranes are key materials for water treatment and desalination. Although surfactants are widely used to tune the interfacial polymerization (IP) process for PA nanofilm formation, their regulatory mechanisms remain incompletely understood. Herein, we synthesized PA nanofilm membranes at a support-free interface in the presence of anionic surfactants with different tail lengths and counterions and comprehensively characterized them to identify the IP mechanism regulated by the surfactant structure. The use of the surfactant with a longer alkyl tail or a smaller/weaker-bound counterion resulted in greater alterations in the structural and physicochemical properties and separation performance of the PA nanofilm membranes. Collaborated with computational simulations, this phenomenon could be attributed to solutal Marangoni instability triggered by the interfacial migration (via binding to PA) of the surfactant complexed with amine monomers during IP. A longer alkyl chain or smaller/weaker-bound counterion of the surfactant intensified Marangoni instability by promoting the interfacial formation of surfactant–amine complexes and/or facilitating their binding to PA, leading to greater PA deformations. Our work provides new insights into the surfactant-regulated IP mechanism as well as a facile means to rationally tailor the properties and performance of IP-assembled nanofilm membranes for various environmental applications.

Plasmonic dielectric antennas for hybrid optical nanotweezing and optothermoelectric manipulation of single nanosized extracellular vesicles.

This paper showcases an experimental demonstration of near-field optical trapping and dynamic manipulation of an individual extracellular vesicle. This is accomplished through the utilization of a plasmonic dielectric nanoantenna designed to support an optical anapole state-a non-radiating optical state resulting from the destructive interference between electric and toroidal dipoles in the far-field, leading to robust near-field enhancement. To further enhance the field intensity associated with the optical anapole state, a plasmonic mirror is incorporated, thereby boosting trapping capabilities. In addition to demonstrating near-field optical trapping, the study achieves dynamic manipulation of extracellular vesicles by harnessing the thermoelectric effect. This effect is induced in the presence of an ionic surfactant, cetyltrimethylammonium chloride (CTAC), combined with plasmonic heating. Furthermore, the thermoelectric effect improves trapping stability by introducing a wide and deep trapping potential. In summary, our hybrid plasmonic-dielectric trapping platform offers a versatile approach for actively transporting, stably trapping, and dynamically manipulating individual extracellular vesicles.

Adsorption of common greywater pollutants and nutrients by various biochars as potential amendments for nature-based systems: Laboratory tests and molecular dynamics

Spruce wood and Typha (wetland plant) derived biochars pyrolyzed at 350 °C and 600 °C were tested for their sorption affinity for organic pollutants (diclofenac, methylparaben, benzotriazole and sodium 1-decanesulfonate) and nutrients (nitrate, ammonium, phosphate and boron) commonly found in greywater. Batch and column studies combined with molecular dynamics modelling determined the sorption capacity, kinetics, and described the underlying mechanisms. The spruce biochar (600 °C) exhibited the highest sorption capacity mainly for the tested organics. The dynamic test performed for spruce biochar (600 °C) showed that the magnitude of desorption was low, and the desorbed amount ranged between 3 and 11 %. Molecular dynamics modelling (a computational tool for elucidating molecular-level interactions) indicated that the increased sorption of nitrate and boron on spruce biochar (600 °C) could be attributed to hydrophobic interactions. The molecular dynamics shows that predominant adsorption of organic pollutants was governed by π-π stacking, with a minor role of hydrogen-bonding on the biochar surface. In summary, higher pyrolysis temperature biochar yielded greater adsorption capacity greywater borne contaminants and the reaction temperature (10–34 °C) and presence of anionic surfactant had a limited effect on the adsorption of organic pollutants, suggesting efficacious application of biochar in general for greywater treatment in nature-based systems.

Transport of polystyrene nanoplastics in porous media: Combined effects of two co-existing substances

Both surfactants and natural organic matters (NOMs) are substances commonly found in aqueous environments, and their effects on the transport of nanoplastics that is gradually gaining widespread attention in porous media are currently in their infancy, while their combined effects are absent. We investigated innovatively the combined effect of surfactants and NOMs on the transport of polystyrene nanoplastics (PS-NPs) in saturated porous media. Adsorption tests of surfactants and NOMs onto PS-NPs, adsorption tests of PS-NPs onto quartz sand, and transport tests of PS-NPs in saturated quartz sand were conducted. Hydrophobicity and Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy were measured and calculated. A mathematical model was employed to fit the transport of PS-NPs in porous media. It was found that the effects and action mechanisms of cationic cetyl trimethylammonium bromide (CTAB) and anionic sodium dodecylbenzene sulfonate (SDBS) on the transport of PS-NPs in porous media were distinct. In the presence of CTAB, 1 mg/L humic acid (HA) and 10 mg/L sodium alginate (SA) could promote aggregation of PS-NPs by decreasing the absolute zeta potential of PS-NPs, and reducing the energy barrier between PS-NPs and porous media and increasing the blocking and straining, thus inhibiting the transport of PS-NPs. In the presence of SDBS, SA and HA could improve the adsorption of SDBS onto PS-NPs by bridging and increasing adsorption sites, thus increasing the hydrophilicity of PS-NPs and improving the transport of PS-NPs. Whether or not NOMs were present, the transport of PS-NPs in porous media was mainly governed by the DLVO interaction energy in the presence of cationic surfactants and by hydrophobicity in the presence of anionic surfactants. This innovative observation has led to an understanding on the environmental behaviour of nanoplastics in porous media under complex environments.

Preparation of Anionic Surfactant-Based One-Dimensional Nanostructured Polyaniline Fibers for Hydrogen Storage Applications

Polyaniline fibers were prepared in the presence of anionic surfactant in an ice medium to nucleate in one dimension and were compared to bulk polyaniline prepared at an optimum temperature. Fourier-transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) were used to investigate the structural analysis of the prepared samples. A conductivity study reveals that polyaniline fibers have high conductivity compared to bulk polyaniline. Hydrogen storage measurements confirm that the polyaniline fibers adsorbed approximately 86% of the total actual capacity of 8-8.5 wt% in less than 9 min, and desorption occurs at a lower temperature, releasing approximately 1.5 wt% of the hydrogen gases when the pressure is reduced further to 1 bar.

Dye-surfactant interaction in aqueous premicellar and micellar environments in the alkaline fading of di-positive methyl green carbocation

The alkaline fading of di-positive methyl green carbocation (MeG2+) has been studied in different aqueous premicellar and micellar environments of anionic, cationic as well as non-ionic surfactants. Mono- and di-negative anions like halides and sulphate have been found to show an inhibiting effect on the fading reaction owing to the formation of dye-anion ion-pair adduct before hydrolysis. The binding strength of the dye-anion ion-pair adduct is in the order: SO42- > I- > Br- > Cl- which rationalizes the same order of inhibition of the rate. A substantial change in the electronic spectra of MeG2+ in the presence of anionic surfactants, sodium dodecyl sulfate (SDS) and dioctyl sodium sulfosuccinate (AOT), in the pre-CMC region indicates a change in the equilibrium distribution of the two stereo isomers of the dye owing to the formation of MeG2+-surfactant ion-pair and ion-pair micelle. The premicellar rate inhibition of the fading reaction by SDS and AOT occurs due to the formation of 1:1 MeG2+-surfactant ion-pair (where ≥ 85 % of MeG2+ remain associated) through electrostatic interaction before hydrolysis. The cationic surfactant cetyltrimethylammonium bromide (CTAB) shows a retarding effect in the post-micellar region as the HO- ion experiences both electrostatic repulsion and steric hindrance to approach the carbocation centre of the dye, embedded in the micelle. The polar hydroxyl group and the polyoxyethylene groups present in the moiety of the non-ionic surfactant Brij35 assist to increase the local concentration of HO- and MeG2+ in the palisade layer resulting in a catalyzing effect on the fading reaction in the post CMC region. Both pre- and post-micellar rate effects have been analyzed quantitatively by different established kinetic models. Detailed calculations have been made to find out different enthalpy and entropy of activation as well as of binding in order to establish the nature of interactions between the dye MeG2+ and monomeric surfactant(s) /micelles as well as solvent molecules. Results of spectrophotometric and tensiometric investigations strongly support the existence of different molecular interactions in different stages of the hydrolysis reaction in the presence of surfactants.

Study on the bactericidal activity of dodecyl dipropylene triamine and anionic mixed surfactant systems

In this study, we anticipated that cocamidopropyl betaine (CAPB) and isomeric alcohol ethoxylates (TO) could protect the antibacterial properties of dodecyl dipropylene triamine (BDA) under the influence of anionic surfactants. Different concentrations of anionic surfactants such as sodium lauryl polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) were added to a mixture of the cationic surfactants BDA and benzalkonium chloride (BZK) with two protective agents: a branched nonionic surfactant TO and a zwitterionic surfactant CAPB. Opticaldensity (OD) and Cell Counting Kit-8 (CCK-8) methods were used to evaluate the antibacterial activity of these systems against sulfate-reducing bacteria (SRB) such as Escherichia coli, Staphylococcus aureus, and Desulfovibrio sp. The protective mechanisms of the different protective agents were studied by measuring their respective viscosities. The protective agents (TO and CAPB) had a negative effect on the biocidal performance of the BZK (C12-C14) but had an excellent protective effect in the presence of anionic surfactants. In the BDA systems (AES and SDS concentrations of 100 mM), the BDA-CAPB-AES, BDA-CAPB-SDS, BDA-TO-AES, and BDA-TO-SDS systemseliminated almost all E.coli and S.aureus bacteria within 2 min of exposure, among which the BDA-CAPB-AES and BDA-TO-AES systems showed the strongest bactericidal activity against sulfate reducingbacteria (SRB). Therefore, these multicomponent surfactant antibacterial systems can potentially be used to replace traditional cationic surfactant systems in the chemical industry, thereby reducing the microbial corrosion caused by SRB.

Interaction of Victoria Blue Dye in Anionic and Cationic Micellar Media: Spectroscopic Study

This manuscript has reported the micellar interaction of cationic triphenylmethane-based dye andquot;Victoria Blue-B (VBB)andquot;. The study was conducted using ionic surfactants viz. Cetyltrimethylammonium Bromide (CTAB)] Sodium Dodecyl Sulphate (SDS), and Sodium Docusate (SD). The behavior of dye in micellar media at concentration ranges of the surfactants mentioned above was monitored by UV-vis absorption spectroscopic study. The solubilization parameters to reveal the interaction of cationic dye in micellar media were assessed. The mathematical calculations of partition constant (Kc), partition coefficient (Kx), binding coefficient (Kb), Gibb’s free energy for partition (ΔGp) and binding (ΔGb) were derived from UV–Vis absorption data. The presence of anionic surfactants caused more bathochromic shifts in the maximum absorption of the dye, which was indicative of strong interactions as compared to the cationic surfactant.

Effect of Tacticity and Degree of Sulfonation of Polystyrene Sulfonate on Calcium-Binding Behavior in the Presence of Dodecyl Sulfate

The hardness-causing ions like calcium are detrimental to the performance of anionic surfactants like dodecyl sulfate. Polystyrene sulfonate is an essential component of ion exchange resins that are used to adsorb such ions. Therefore, understanding the binding behavior of calcium ions to polystyrene sulfonate in the presence of dodecyl sulfate is of industrial relevance. Two important structural parameters of polystyrene sulfonate are known to influence its behavior: (i) The arrangement of aromatic groups around the carbon backbone (tacticity) and (ii) the degree of sulfonation. We use molecular dynamics simulations to study the effect of the above two parameters on the calcium-binding to polystyrene sulfonate in the presence of dodecyl sulfate. We observe that the calcium-binding ability and its response to the dodecyl sulfate are highly sensitive to the arrangement of aromatic groups around the backbone. We identify one atactic structure of 100% sulfonated polystyrene sulfonate and another of 20% sulfonated polystyrene sulfonate that shows a significant increase in calcium ion binding upon the addition of dodecyl sulfate ions. The increase in the 100% sulfonated structure is due to the formation of calcium ion bridges between the sulfonate groups located on one side of the backbone. The increase in the 20% sulfonated structure is due to the increase in the sulfonate-Ca-Cl type of ion bridges. We also observe a stronger association between dodecyl sulfate and low sulfonated polystyrene sulfonate because of the hydrophobic interaction between polystyrene sulfonate’s backbone and the hydrocarbon tail of dodecyl sulfate. However, aligning all the aromatic groups on the same side of the backbone (isotactic structure) sharply weakens the association between the two species. Our results can aid in achieving the desired water softening capacity of ion exchange resins in the presence of anionic surfactants via altering the tacticity and degree of sulfonation.

First Report for the Electrooxidation of Antifungal Anidulafungin: Application to its Voltammetric Determination in Parenteral Lyophilized Formulation Using a Boron‐doped Diamond Electrode in the Presence of Anionic Surfactant

AbstractIn this paper, for the first time, the study of electrochemical oxidation and electroanalytical determination of anidulafungin (ANF), a semi‐synthetic echinocandin with antifungal activity was conducted. For this purpose, a commercially available boron‐doped diamond (BDD) electrode pretreated electrochemically (anodic and subsequent cathodic) was used. Employing cyclic voltammetry, the compound presented a single and irreversible oxidation step. The electrode process is controlled by a dual mechanism of diffusion and adsorption. A systematic study of various experimental conditions, such as the effect of electrode pretreatment, pH and the nature of the supporting electrolyte, surfactant, accumulation variables, and instrumental parameters on the adsorption behavior of ANF, was carried out by using square‐wave voltammetry. When the stripping mode (after 90 s accumulation at +0.3 V) was applied in 0.1 mol L−1 HNO3 containing 3×10−4 mol L−1 SDS, there was a linear dependence between the oxidation peak current at +1.29 V and the ANF concentration in the range from 0.1 to 10.0 μg mL−1 (8.8×10−8–8.8×10−6 mol L−1). The limit of detection value was found to be 0.021 μg mL−1 (1.8×10−8 mol L−1). Practical applicability of the proposed method was demonstrated in commercial parenteral dosage form.

Separation performance of ultrafiltration during the treatment of algae-laden water in the presence of an anionic surfactant

Ultrafiltration was demonstrated to be an effective and efficient method to treat algae-laden water. However, the presence of compounds such as surfactants can act as a stimulus for algae outbreak and change the characteristics of algae cells and derived organics. Therefore, it is necessary to investigate the filtration and separation performance of ultrafiltration during the treatment of algae-laden water in the presence of anionic surfactants (the most widely used surfactant type). In this study, sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (LAS) were employed respectively to simulate the presence of a low concentration of an anionic surfactant in eutrophicated water. It was found that surfactants present in natural waters could enhance the hydrophilicity of the algae interface and the stability of the algae-laden water system with mitigated algae aggregation. During the initial filtration process, membrane fouling was aggravated related to the more serious pore blocking induced by the present SDS or LAS; however, during the next stage, membrane fouling was alleviated due to the formation of a looser cake layer in the presence of SDS or LAS. The pore blocking at the earlier stage contributes more to the decrease of total flux when surfactants are involved. Furthermore, the disinfection byproduct formation potential was reduced with SDS or LAS mainly due to the degradation of free available chlorine by the surfactants. While the concentration of algal toxins was ascended in the ultrafiltration effluent, which indicates that the separation performance was highly impacted by the presence of anionic surfactant.

Electro-kinetically tailored interfaces for chemical enhanced oil recovery in carbonates

SmartWater flooding through the injection of optimized chemistry water has lately become an attractive proposition for improved/enhanced oil recovery (IOR/EOR) in carbonate reservoirs. The wettability alteration towards water-wet conditions caused by favorable surface charge alteration is identified as the main mechanism responsible for oil recovery. In this experimental investigation, the impact of SmartWater/surfactant synergy on wettability alteration was thoroughly studied by measuring zeta-potentials at calcite/brine and crude oil/brine interfaces using electrophoresis technique. Different types of surfactants are considered including: anionic, amphoteric and non-ionic. Four different low salinity water recipes including SmartWater (10-times reduced high salinity water) as well as the high salinity water (HSW) were chosen for zeta potential measurements. The results showed that both anionic surfactants increased the magnitude of the negative zeta-potentials at the interfaces by almost same order of magnitude. The negative zeta-potentials were increased the most with anionic surfactants in the low salinity NaCl brine, from (−15 to −21 and up to −37 mV) at the calcite interface and from (−6 to −19 mV) at the oil interface. SmartWater showed relatively higher negative zeta-potentials for calcite when compared to low salinity Na2SO4 brine and HSW in the presence of anionic surfactant. These results indicate that both NaCl brine and SmartWater can synergistically combine with anionic surfactants for effective wettability alteration in carbonates. Amphoteric surfactant showed a negligible impact on electrical double layer (EDL) expansion and consequently the wettability alteration. The nonionic surfactant induced electrostatic repulsion forces at both calcite/brine by shifting the zeta potentials from (+5.9 to −6.3 mV) and crude oil/brine interface from (−0.2 to −4.7 mV) respectively in high salinity water. As a result, nonionic surfactant can be considered as the best chemical formulation to reduce interfacial tension and cause wettability alteration in conventional chemical flooding processes. The negligible impact of adding surfactant chemicals on the measured di-electric constant of different brines confirmed the robustness of zeta-potential values reported in this study. This work for the first time evaluated the synergistic effects of different brines including the SmartWater with surfactant chemicals by measuring zeta-potentials at calcite/brine and oil/brine interfaces. The optimally suited water recipes were identified to synergistically combine with these chemicals to enhance wettability alteration in carbonates. The new knowledge gained from this electro-kinetic study will provide practical guidance on how to design efficient chemical flooding processes for wettability alteration and enhanced oil recovery in carbonates.

Efficient and Direct Exfoliation of High-Quality Graphene Layers in Water from Different Graphite Sources and Its Electrical Characterization

Green and efficient mass production of graphene sheets with high quality and electrical conductivity is intriguing for both academic scientists and industry. Among numerous production methods suffering from complexity or harsh chemical media, direct and high-yield exfoliation of graphite in water seems to be the best choice. In this study, efforts were made to prepare high-quality and stable graphene dispersions with the highest possible concentrations through an ultrasound-assisted liquid-phase exfoliation (LPE) in water directly from two types of natural graphites. The rigorous structural, morphological and electrical analyses were conducted on both graphite and graphene samples to quantitatively identify the effect of graphite sources on the LPE yield and the quality of the graphene nanosheets produced in the presence of an ionic surfactant. The results obtained by TEM, AFM, XRD and Raman spectroscopy indicated the successful and efficient production of single and few layer graphene sheets with the remarkable concentration of 3.18[Formula: see text]mg.ml[Formula: see text] in water. Moreover, the results signified that the structural quality, electrical conductivity and production yield of the graphene layers undoubtedly depend on the structural properties of graphite source. In fact, the graphite source greatly influences the final properties and potential applications of the produced graphene layer and the results are so important for the future graphene industry.

Display of hidden properties of flexible aerogel based on bacterial cellulose/polyaniline nanocomposites with helping of multiscale modeling

Tuning the synthesis conditions of polyaniline (PANI) such as aniline monomer’s protonation states and adding surfactants into polymerization mixture or even the existence of bacterial cellulose (BC) had a substantial influence on the final properties. To explore the relationship between components presented in the polymerization mixture, simulation tools (molecular dynamics (MD)/Monte Carlo (MC)/Density functional theory (DFT)) can be used. Herein, nanocomposite aerogels of BC/PANI were fabricated in the presence of anionic surfactants; sodium dodecyl benzene sulfonate (SDBS) or sodium dodecyl sulfonate (SDS) at two different concentrations (0.05 M and 1 M) of HCl solution. Two types of aniline monomers were considered in the polymerization mixture based on HCl solution’s concentrations including neutral and protonated aniline in 0.05 and 1 M, respectively. Various morphologies from nanobelts (with a width of 100–500 nm) and polyhedrons (with a thickness of 100–700 nm) in 0.05 M of acid solution in the presence of SDBS or SDS, respectively, were detected. Based on DFT computations it was found that electrostatic interactions and the formation of hydrogen bonds play a vital role in the interfacial interaction mechanism between both surfactants (SDBS and SDS) and different protonation forms of aniline monomers. Nevertheless, in the case of SDBS and aniline monomers (in both 0.05 and 1 M of HCl solutions), an excess interaction mechanism, namely π-π stacking, was observed, which enhanced the interaction between them and confirmed by experimental results. Therefore, the highest conductivity of 0.8 S/cm was obtained for the BC/PANI prepared with SDBS in 1 M of HCl solution. Besides, the smallest energy gap of 2.74 eV was predicted from DFT calculations for this sample that further confirmed its high electrical properties and smaller band gap at 3 nm, which was also confirmed by MD and MC.

Influence Of The Size Of Colloid Nanorized Systems On The Luminescence Intensity Of Eu(III) And Tb(III) Complexes

Optimal conditions for complexation of Tb(III) ions with norfloxacin, keterolac, 2-oxo-4-hydroxyquinoline-3-carboxylic acid amide derivative and Eu(III) with oxytetracycline were established. The dependence of the luminescence intensity (Ilum) of complexes on the acidity of the medium, the type of solvent, the luminescent characteristics of complex compounds were determined, the average lifetime of the excited state of europium and terbium ions in complex compounds in the presence and absence of cationic, anionic and nonionic substances, and the size of colloidal nanoscale systems based on these complexes is established. Analysis of the influence of the type of surfactants on the processes of excitation energy transformation in the complexes of Eu(III), Tb(III) with some drugs was studied by the method of dynamic light scattering. It was found that the luminescence intensity of colloidal nanoscale systems based on Tb(III) and Eu(III) complexes increases in the presence of cationic surfactants(СPC) and nonionic surfactant (Triton X-100), which is associated with a decrease in their size, although other factors may be involved: synergetic effects, displacement of water molecules from the internal coordination sphere of the complex and increasing the rigidity of the complex during coordination with surfactants. Exceptions are Eu – OxTc, Tb-R2, Tb-Nor complexes in the presence of anionic surfactants (SDS), the size of which increases, which can be explained by the formation of triple complexes. The intensity of their luminescence increases, because in these cases there is a displacement of water molecules from the internal coordination sphere of the complex in coordination with SDS.

Effect of Anionic Amphiphiles on the Morphology of Hexagonal Plate-like ZnO Particles.

Zinc oxide (ZnO) particles were synthesized in the presence of anionic surfactants (ASs). The effect of ASs on the morphology of the ZnO particles was investigated by using ASs with various alkyl chain lengths and changing the molar ratio of AS/ZnSO4. Hexagonal plate-like ZnO particles were formed in the presence of ASs. Adsorption of the AS on the c face of the ZnO crystals inhibited (promoted) crystal growth along the c-axis (ab-axis) direction. Increasing the molar ratio of AS/ZnSO4 decreased the particle thickness, owing to the resulting increase in the coverage of the c face with AS. The particle diameter of the hexagonal plate-like ZnO particles (the diagonal length of the hexagonal plate) increased with increasing alkyl chain length of AS as a result of the van der Waals interactions between the alkyl chains. The data indicate that the particle diameter and thickness can be controlled by fine-tuning the van der Waals interactions between the alkyl chains and the coverage of the c face of the ZnO particles with AS.