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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]

The ability to detect pathogenic microbes in water and food samples is of prominent interest, but it remains a great challenge. Herein, we report a simple fluorescence sensor based on amphiphilic conjugated polythiophene (ACPT) for the detection of gram‐negative pathogenic bacteria, Escherichia coli,in pH 7.0. The ACPT sensor was synthesized by the oxidative polymerization of water‐soluble thiophene monomers in an aqueous solution. The ACPT sensor undergoes the fluorescence “turn on” response at 432 nm upon the addition of E. coli. The ionic complex, which is generated by electrostatic interaction during the short incubation time of 15 min, resulting in the enhancement of the fluorescence intensity of ACPT. The application of ACPT enables the detection of E. colipathogens in tap water and milk samples with good recoveries of 96.94–100.83% and 93.27–116.75%, respectively, and excellent reproducibility (n= 3, relative standard deviation [RSD] = 1.78%). The current findings pave the way for the promising application of a novel ACPT system that could be used in food safety and environmental monitoring. A simple fluorescence sensor based on amphiphilic conjugated polythiophene (ACPT) was developed for the detection of gram negative pathogenic bacteria, Escherichia coli. ​

A series of cationic surfactants were synthesized from chemical modification of 4-aminoantipyrine. The chemical structures were confirmed using infrared (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopy. The surface activities of the surfactants in their solutions were determined by surface tension measurements. Increasing the hydrophobic chain length increased the surface activity of the surfactants in solutions. Measurements of interfacial tension between surfactants solutions and light paraffin oil showed that the interfacial tension values were decreased with increasing the alkyl chain length. The emulsion stability measurements showed the applicability of these surfactants as emulsifying agents. The foaming power measurements showed the synthesized surfactants have low ability for foam formation. Thermodynamic properties of adsorption and micellization processes showed their tendency towards adsorption at solution interface and micellization in their solutions. Results showed reasonable surface activities compared to conventional cationic surfactants. The antimicrobial activity of the synthesized surfactants against Gram-positive bacteria (Bacillus subtilisand Staphyl. aureus,Gram-negative bacteria (Pseudomonas aeruginosaand E. coli.) and Fungi (Candida albicansand Aspergillus niger) was evaluated. The efficiency of these compounds as antimicrobial agents) was increased with the hydrophobicity and carbon chain length.

Naturally modified nonionic alginate-based polymers were synthesized to act as functionalizing agents for upconversion nanoparticles (UCNPs). The synthesized polymer-UCNPs hybrid nanoparticles show high stability, excellent biocompatibility and enhanced luminescence intensity for NIR imaging. Additionally, our results show that due to the large cavities of the materials and amphiphilic polymer shell, these nonionic alginate-functionalized UCNPs were able to load the anticancer drug doxorubicin (DOX) with the exceptional efficiency as well as release it in a highly controlled and selective pH-responsive manner via folate receptor-mediated endocytosis. Targeting using this multifunction polymer significantly improved the capability of DOX-loaded UCNPs to inhibit the growth of KB cancer cells than free DOX. These biocompatible nonionic alginate-functionalized UCNPs hold substantial potential as effective anticancer drug-delivery carriers and NIR imaging agents. [ABSTRACT FROM AUTHOR]

A new series of some cationic surfactants were synthesized namely: 2-(2-(2-(dodecanoyloxy)ethoxy)ethoxy)-N,N,N-tris(hydroxymethyl)-2-oxoethanaminium (DDAC); N,N,N-tris(hydroxymethyl)-2-oxo-2-(2-(2-(tetradecanoyloxy) ethoxy)ethoxy) ethanaminium (TDAC) and N,N,N-tris(hydroxymethyl)-2-oxo-2-(2-(2-(hexadecanoyloxy)ethoxy)ethoxy)ethanaminium (HDAC). The chemical structures of the synthesized cationic surfactants were confirmed using FT-IR and 1H-NMR spectroscopies. The surface tension of the synthesized cationic surfactants was measured at 25, 40 and 55°C. The surface parameters were determined from the surface tension measurements. The emulsification power and foaming power measurements showed the applicability of these surfactants in the oil field. The biological activity of the synthesized surfactants was measured against pathogenic bacteria (Staphylococcus aureusand Escherichia coli) and fungi (Candida albicansand Aspergllus niger) using inhibition zone diameters. The obtained data revealed that the dodecanoate derivative (DDAC) has more antimicrobial activity against the investigated microorganisms than tetradecanoate and hexadecanoate derivatives (TDAC and HDAC).

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]

Fungi have long been identified as causal agents of plant diseases. The development of plant antifungal activity was attempted by synthesis of a new type of anionic and nonionic surfactant. The surface properties were studied, including critical micelle concentration (CMC), effectiveness ( π cmc ), maximum surface excess ( Γ max ), and minimum surface area ( A min ). Free energy of micellization and adsorption was calculated (Δ G ° mic and Δ G ° ads ). The antifungal activity of the prepared surfactants was verified in vitro by the poisoned food technique against eight phytopathogenic fungi: Colletotrichum dematium , Drechslera hawaiiensis , Fusarium oxysporum , Fusarium solani , Humicola fuscoatra , Pestalotia laurocerasi , Phoma spp., and Phytophthra . The results reported that the percentage inhibition of mycelial growth increases with increasing concentrations of the surfactant for all fungal species used. These results indicated that the surfactant inhibited the mycelial growth of all fungal species in a dose-dependent manner. Blend surfactants have a potential antifungal effect for the control of some phytopathogenic fungi. [ABSTRACT FROM AUTHOR]

Three biodegradable gemini cationic surfactants were synthesized and namely: N , N ′-bis(2-hydroxyethyl)- N , N ′-dimethyl- N , N ′-bis(2-(tetradecanoyloxy) ethyl)ethane-1,2-diaminium bromide; N , N ′-bis(2-hydroxyethyl)- N , N ′-dimethyl- N , N ′-bis(2-(tetradecanoyloxy) ethyl) hexane-1,6-diaminium bromide and N , N ′-bis(2-hydroxyethyl)- N , N ′-dimethyl- N , N ′-bis(2-(tetradecanoyloxy) ethyl)dodecane-1,12-diaminium bromide. The chemical structures of these compounds were characterized by FTIR, 1 H NMR and elemental analysis spectroscopy. The surface parameter including: the critical micelle concentration (CMC), effectiveness ( π cmc ), efficiency (Pc 20 ), maximum surface excess ( Γ max ) and minimum surface area ( A min ), were calculated from it is surface tension measurements. The synthesized surfactants showed higher surface activity. The thermodynamic parameters showed that adsorption and micellization processes are spontaneous. It is clear that the synthesized surfactants showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. The synthesized compounds were applied on the field of biocide via measuring there efficiency against different strain of pathogenic bacteria and fungi as well as sulfate reducing bacteria using inhibition zone diameters method and minimum inhibition concentration values. The synthesized compounds showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative and fungi as well as sulfate reducing bacteria. The biodegradability of the synthesized surfactants was tested in river water using Die-away method and showed their readily biodegradation in the open environment. The CMC of mixtures in equal mole fraction (G2 + G6 (5:5), G2 + G12 (5:5), G6 + G12 (5:5)) and the CMC of mixtures was compared with pure gemini surfactants. Also the mixed micellization parameters were calculated. [ABSTRACT FROM AUTHOR]

Different fatty acid namely; palmitic, stearic, oleic and linoleic acids and polyethylene glycol-600 were reacted to give nonionic surfactants. The formed nonionic surfactants were reacted with germanium dioxide in presence of sodium carbonate to form germinates nonionic surfactants (I, II, III, and IV). The chemical structures of the synthesized surfactants were characterized by FT-IR and 1 H-NMR spectra. The synthesized surfactants showed higher surface activity at different temperature and surface parameters influenced by chemical structure of surfactants. The thermodynamic calculations showed that adsorption and micellization processes are spontaneous. The synthesized surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The promising inhibition efficiency of these compounds against the sulfate reducing bacteria facilitates them to be applicable in the petroleum field as new categories of sulfate reducing bacteria biocides. [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]

Abstract: The three cationic surfactants based on Schiff base were laboratory prepared, (E)-decyl-4-[(2-hydroxyethylamino) methyl]-N,N-dimethyl benzenaminium bromide (I), (E)-dodecyl-4-[(2-hydroxyethylamino)methyl]-N,N-dimethyl benzenaminium bromide (II) and (E)-hexadecyl-4-[(2-hydroxyethylamino)methyl]-N,N-dimethyl benzenaminium bromide (III) were evaluated as corrosion inhibitors for carbon steel in acid medium and antimicrobial agents against sulfate reducing bacteria, SRB. Three techniques were used for the corrosion inhibition evaluation, namely; weight loss, polarization and electrochemical impedance. The serial dilution method was used to evaluate the inhibiting effect of these compounds on the sulfate reducing bacteria growth. The results showed that the prepared compounds have good antimicrobial activities against the SRB as well as they have high efficiency as corrosion inhibitors for carbon steel in 1M HCl. [Copyright &y& Elsevier]

The phenomenon of corrosion of metals including Fe, Al, Cu, Zn, Mg and their alloys is controlled to a great extent by selection of highly corrosion resistant inhibitors. The associated cost factor favors the use of cheap metallic materials along with efficient corrosion prevention methods in many industrial applications. In this aspect, corrosion inhibitors have a significant role in the protection of metals from corrosion. These inhibitors are either hazardous chemicals or environmentally friendly chemicals. Many authors reported that the use of plants extracts from mango, cashew, passion-fruit, orange, khillah seeds, African bush pepper, neem leaves and papaya as corrosion inhibitors in an acid medium for protection of metals such as steel, copper, and copper alloys gave high inhibition efficiency. Some environmentally friendly chemicals namely, octanoic acid, 2-ethylhexanoic acid and their alkali salts, sodium borates, triazoles, hydrocarbyl, and benzotriazoles were used as corrosion inhibitors. Polymeric compounds such as polyacrylic, polymaleic, and polyaspartic acid and its salts were also used as corrosion inhibitors for acidic ferrous metal surfaces in contact with acidic corrosive aqueous saline environment saturated with carbon dioxide. Published patents related to the corrosion inhibition using green corrosion inhibitors are discussed.

Two series of cationic Schiff base surfactants, namely, 2‐(benzylideneamino)‐3‐(2‐oxo‐2‐alkoxyethyl)‐1,3‐benzoimidazol‐3‐ium bromide (IA–D)and 2‐[(4‐methoxybenzylidene) amino]‐3‐(2‐oxo‐2‐alkoxyethyl)‐1,3‐benzoimidazol‐3‐ium bromide (IIA–D)were prepared. The chemical structures of the prepared Schiff bases were recognized by elemental analysis, FTIR, H NMR, C13‐NMR and GC/MS spectra. The surface activities of the synthesized Schiff base cationic surfactants showed their tendency towards adsorption at the air/water interface. The adsorption tendency was estimated from the values of surface tension and the depression of surface tension at the critical micelle concentration. The studied surfactants were evaluated as antimicrobial agents against pathogenic and sulfur‐reducing bacteria using inhibition zone diameters and minimum inhibition concentration values. The synthesized cationic benzoimidazolium Schiff base cationic surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The synthesized compounds were tested for the activity as corrosion inhibitors against carbon steel corrosion in 0.5 M HCl at 200 and 400 ppm. The promising inhibition efficiency of these compounds against the sulfur‐reducing bacteria facilitates them to be applicable in the petroleum field as new categories of Sulfur Reducing Bacteria biocides. The inhibition efficiencies of the tested compounds showed good inhibition and protection of the carbon steel. The corrosion inhibition tendency correlated to the surface activity and chemical structure of the compounds.

Eight novel uracil-based cationic surfactants containing Schiff base species were synthesized and characterized using elemental analysis, FTIR, 1H-NMR and 13C-NMR spectroscopy. The surface activities of the synthesized Schiff bases and their cationic derivatives were determined based on interfacial tension measurements and partition coefficient values in water/octanol system. The synthesized Schiff bases and their cationic derivatives were evaluated as novel biocides against different bacteria and fungi strains. The results showed that the biocidal activity of the synthesized Schiff bases was considerably increased by quaternization. The influence of the cationic surfactants as biocides was increased by increasing the hydrophobic chain length and the presence of the methoxy groups. The biocidal activity was also increased by increasing the partition coefficient in water/octanol system. The structure and surface activity/biocidal activity of the different compounds were discussed.