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[Display omitted] • Self-assembled (SA) surfactants were synthesized, and investigated as corrosion inhibitors. • Polarization studies indicated that SA acted as a mixed-type inhibitors for Cu in 1 M HNO 3 solution. • Adsorption studies indicated that the inhibitors obeyed Langmuir isotherm model. • The theoretical calculations are correlated well with experimental techniques. Three novel self-assembled phenyl pyrazole cationic surfactant derivatives, coded as SA-6, SA-12, and SA-18, were synthesized, structure confirmed, and examined as eco-friendly corrosion inhibitors for Cu in 1 M HNO 3 electrolyte using open circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) measurements. The efficacy of these surfactants was pointedly influenced by dosage (5 × 10−5 M − 1 × 10−3 M), attaining a maximum of 90.9 %, 92.9 %, and 94.5 % for SA-6, SA-12, and SA-18, respectively, at 1 × 10−3 M. The fact that the highest shift in corrosion potential (E corr) is so minor suggests that the compounds under investigation are inhibitors of the mixed type (anodic/cathodic). The high value of K ads and the negative Δ G ads o value (−35.0, −35.8, and −36.8 kJ mol−1) suggests that the SA-6, SA-12, and SA-18 inhibitors have a strong and spontaneous tendency to adsorbed onto the Cu substrate. The development of the self-assembled surfactant defensive film on the Cu substrate was morphologically verified by atomic force microscopy (AFM). The studied self-assembled surfactants adsorbed physically and chemically according to Langmuir isotherm model. Quantitative structure–activity relationship (QSAR) was used to construct the prediction model for SA-6, SA-12, and SA-18′s anti-corrosion properties, while density functional theory (DFT) calculations were used to determine the chemical descriptors linked to the frontier molecular orbitals (FMOs). It was shown that the results of the computational and electrochemical experiments were highly consistent. [ABSTRACT FROM AUTHOR]

Despite corrosion being an inevitable process, researchers strive to control corrosion. In this study, our goal was to prepare two amido Gemini cationic surfactants, LAPG and MAPG, each with different alkyl chains and multiple carbonyl groups as rich electronic rich centers. We aimed to evaluate these surfactants as potential corrosion inhibitors for carbon steel (CS) in 1 M HCl at temperatures of 25–55 ± 0.1 °C. In theoretical investigations, DFT parameters and Mont Carlo simulation were run to predict the adsorption affinity and reactive sites of the LAPG and MAPG molecules. Their efficacy was investigated experimentally considering weight loss and electrochemical techniques. The Tafel polarization revealed that at 0.1 mM of LAPG and MAPG, the corrosion current density (icorr) of CS was reduced to the lowest extent (75.56 and 53.82 μA cm−2) compared to 529.3 μA cm−2in the absence of the inhibitors. EIS data suggests the enhancement of the thickness of the adsorbed layers of the studied compounds from the decrease of the double-layer capacitance Cdlvalues. The Langmuir isotherm explained the adoption phenomena of these compounds at 25–55 ± 0.1 °C. Activation and adsorption thermodynamic parameters predicted the chemisorption behavior of these molecules onto the steel surface. AFM and XPS tools confirm the CS surface protection due to these inhibitors’ adsorbed layer. A parallel study showed the superiority of these corrosion inhibitors in HCl compared with those reported earlier, making these compounds highly promising corrosion inhibitors, especially in high-temperature acidic environments.

Quaternary ammonium salts are frequently used as antimicrobial agents that disrupt cell membrane through the binding of their ammonium cations to anionic sites in the outer tissue of bacteria. This article describes the synthesis of Gemini quaternary ammonium salts (G600Br, G1000Br and G1500Br). The chemical structures of synthesized Gemini quaternary ammonium salts were confirmed using FT-IR and 1 HNMR spectra. The surface activity of the synthesized surfactants were determined from the surface and interfacial tension measurements. The surface parameter including: the critical micelle concentration (CMC), effectiveness ( π cmc ), efficiency ( P c 20 ), maximum surface excess ( Γ max ) and minimum surface area ( A min ), were calculated from the surface tension measurements, also, the foaming and emulsification power were measured. The thermodynamic parameters of micellization and adsorption showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. Screening tests of the synthesized compounds showed that the compounds exhibit an effective antimicrobial activity on a variety of bacteria including Gram-positive bacteria ( Bacillus subtilis and Micrococcus luteus) , Gram-negative bacteria ( Bordetella pertussis and Escherichia coli) and Fungi ( Candida albicans and Aspergillus niger) . [ABSTRACT FROM AUTHOR]

Silver nanoparticles loaded by three Gemini cationic surfactants having different spacer chain length were prepared and characterized using ultraviolet–visible (UV–vis) absorption spectroscopy and transmission electron microscope (TEM) analysis. TEM analysis showed the homogeneity and stability of the formed silver nanoparticles in the presence of the Gemini surfactants. The results showed increased activity of the silver nanoparticles in the presence of the Gemini cationic surfactants. Antimicrobial results of inhibition zone diameter and minimum inhibitory concentration were correlated to Gemini surfactants and their nanoparticles including surface activity and tendency toward adsorption at interfaces. [ABSTRACT FROM AUTHOR]

Here in, the new gemini anionic surfactants with different alkyl chain length were synthesized (C8A, C12A, C16A and C18A). The chemical structure of the synthesized surfactants was confirmed using infra-red spectroscopy (IR) and proton nuclear magnetic resonance spectroscopy ( 1 H NMR). Silver nanoparticles colloidal solution of 20–25 nm diameters was prepared using trisodium citrate as reducing agent. The nanostructure of the synthesized surfactant with silver nanoparticles with diameters ranging from 6.3 to 23.2 nm was prepared and characterized using ultra violet spectrophotometer (UV), transmission electron microscope (TEM), dynamic light scattering (DLS) and energy dispersive X-ray (EDX). The results declare formation and stabilization of silver nanoparticle using synthesized anionic surfactants. Antimicrobial activity of the synthesized anionic surfactants and their nanostructure with silver nanoparticles were evaluated against pathogenic bacteria and fungi. The antimicrobial activity showed the enhancement in the antimicrobial activity of the synthesized gemini anionic surfactants in the nanostructures form. [ABSTRACT FROM AUTHOR]

Here in, the nanostructure of dithiol surfactants were synthesized with gold nanoparticles (AuNPs). The nanostructure of these surfactants was investigated using FTIR, UV, XRD, and TEM techniques. The surfactants under investigation show good ability for assembling on AuNPs. The alkyl chain length shows strong effect on the stabilization of the nanostructure of these surfactants. The detection of Ni2+ and Zn2+ ions in water solution was investigated using UV spectrophotometer. The data show that the sensitivity of the nanostructure of surfactants towards the detection of Ni2+ and Zn2+ ions is more than that of the individual surfactants. [ABSTRACT FROM AUTHOR]

In the present study newly developed potentiometric sensors for determination of zinc(II) are presented. The proposed potentiometric method was based on the fabrication of modified carbon paste (MCPE; electrode X) and modified gold nanoparticles-carbon paste (GNPs-CPE; electrode IX) sensors. A mercapto compound of 1,4-bis(5-mercaptopentyloxy)-benzene (BMPB) alone or self-assembled on gold nanoparticles was used as modifier to construct electrode (X) and electrode (IX) sensors, respectively. The prepared electrodes exhibit Nernstian slope of 29.93±0.4 and 26.0±1.02mVdecade-1 towards Zn(II) ion over a wide concentration range of 6.8 x 10-10 to 2.9 x 10-2 and 1.0 x 10-7 to 1.0 x 10-2molL-1 for electrode (IX) and electrode (X) sensors, respectively. The limit of detection of the electrode (IX) and electrode (X) sensors was found to be 6.8 x 10-10 and 1.0 x 10-7molL-1, respectively. The potentiometric response of the electrode (IX) and electrode (X) based on GNPs-BMPB and BMPB are independent of pH of test solution in the pH range of 2.5-8.1 and 3-7 with a response time of 6 and 8s for electrode (IX) and electrode (X) sensors, respectively. The proposed sensors showed fairly good discriminating ability towards Zn(II) ion in comparison with many hard and soft metal ions. Finally, the proposed electrodes were successfully used as indicator electrodes in potentiometric titration of zinc ion with sodium tetraphenylborate (NaTPB) and in direct determination of Zn(II) ion in some water samples. The results obtained compared well with those obtained using atomic absorption spectrometry. [ABSTRACT FROM AUTHOR]