D. A. Ismail

Enhancement of the Surface Activity for Some Monomeric and Polymeric Thiol Surfactants Using Silver Nanoparticles

In the present work, the self-assembling of some synthesized thiol surfactants namely (6-(3-amino phenoxy) hexane-1-thiol, 8-(3-amino phenoxy) octane-1-thiol, 10-(3-amino phenoxy) decane-1-thiol, 12-(3-amino phenoxy) dodecane-1-thiol, and their polymers on silver nanoparticles was investigated. The self-assembling of these surfactants on silver nanoparticles was characterized using different techniques such as ultraviolet (UV) spectroscopy, powder x-ray diffraction (XRD), electrone diffraction (ED), and transmission electron microscopy (TEM). The effect of the self-assembling of these surfactants on the stabilization of the silver nanoparticles (AgNPs) was studied using TEM images. The growth of the silver nanoparticles was investigated with respect to the increase of alkyl chain in the synthesized thiol surfactants. The effect of silver nanoparticles on the surface, interfacial tension, and the emulsion stability of these surfactants with paraffin oil was studied. The results show that the silver nanoparticles have the ability to effect on the behavior of these surfactants in solution and improve their surface activity.

Synthesis and Surface Properties of Novel N-Alkyl Quinoline-Based Cationic Gemini Surfactants

Two series of cationic dimeric (gemini) surfactants are prepared with respect to key surfactants properties, such as surface activity and solubilization. The influence of both the dimerization and the spacer group is examined in order to establish structure-property relationships. The surface tension and critical micelle concentration can be markedly reduced compared to the monomeric surfactants in the pure state. The critical micelle concentration (cmc) of each series has been determined using equilibrium surface tension measurements. Furthermore, air/water interface parameters including effectiveness (πcmc), efficiency (PC20), maximum surface excess (Γ max ), and minimum surface area (A min ) have been also derived using Gibbs adsorption equation at 25°C. Standard free energies of micellization and adsorption were calculated. Solubilization behaviors of the synthesized surfactants were measured towards paraffin oil as solubilized material using light transmission technique.

Synthesis and Properties of Some N-Acylethylenediamine Triacetic Acid Chelating Surfactants

Abstract A new kind of surfactants with chelating properties named N-acylethylenediamine triacetate (N-acyl ED3A) of different hydrocarbon chain lengths were synthesized from anhydrous ethylene diamine, fatty acid chlorides (Capryloyl, lauroyl, myristoyl, palmitoyl, stearoyl or oleoyl chloride) and chloroacetic acid. The chemical structures of the prepared compounds were confirmed using different spectroscopic techniques, primarily Fourier transform infrared spectroscopy and nuclear magnetic resonance. The surface properties including surface and interfacial tension, foaming height, emulsification power, calcium ion stability, stability to hydrolysis and critical micelle concentration (CMC) were determined. The trisodium N-acylethylenediamine triacetates have been found to combine the properties of strong surfactancy, extreme mildness with a high tolerance to water hardness, and ability to chelate metal ions, which indicates a promising application prospect in many fields.

Synthesis and Biological Activity of Alkyl Pyridinium Aldoxime Based Surfactants

Abstract A series of N-alkyl pyridinium aldoxime surfactants was synthesized by the reaction of pyridinium aldoxime with long chain alkyl halides (decyl, dodecyl, tetradecyl and hexadecyl bromide). The chemical structure of the synthesized compounds was confirmed by elemental analysis and FTIR spectra. Surface tension was measured in aqueous solutions for different concentrations at 25 °C. Various surface properties of the synthesized surfactants were evaluated, particularly the critical micelle concentration (CMC), effectiveness (πCMC), efficiency (PC20) as well as the maximum surface excess (Γmax) and minimum surface area (Amin). Also, the micellization and adsorption at liquid/air interfaces were investigated. The synthesized cationic surfactants were evaluated for their biocidal activity. Good antibacterial and antifungal activities were recorded against Gram-positive bacteria (Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 25922), followed by Gram-negative bacteria (Escherichia coli ATCC 23282, Pseudomonas aeruginosa ATCC 10145), yeast (Candida albicans IMRU 3669) and filamentous fungus (Aspergillus niger ATCC 16404).

Preparation and Evaluation of Some Surface Active Esters

A series of three homologous pure nonionic surfactants, all mono esters of tri(ethylene glycol), were synthesized. The ester surfactants varied in carbon chine length. The surfactant was characterized by determining surface properties of their solutions, including surface tension, critical micelle concentration, effectiveness (πcmc), efficiency (PC20), maximum surface excess (Γ max ), and minimum surface area (A min ). Standard free energies of micellization and adsorption were calculated. Solubilization behaviors of the synthesized surfactants were measured towards paraffin oil as solubilized material using light transmission technique. Base-catalyzed hydrolysis was investigated by using tensiometry.

Surface-active properties of new cationic gemini surfactants with cyclic spacer

ABSTRACT Three cationic gemini surface active compounds of the type (1r,4r)-1,4-dialkyl-1,4-dimethy-l-piperazine-1,4-diium bromide (Ia, Ib, and Ic), were synthesized. They were characterized using elemental analysis and 1H-NMR spectra. Their surface-active properties were measured in aqueous solutions with different concentrations at different temperatures (25, 40, and 55°C). Various surface measurements of these gemini surfactants, (compared to the conventional one, 1-Dodecyl-1-methylpiperidinium bromide (a)) were estimated, specifically critical micelle concentration (CMC), effectiveness (πCMC), efficiency (PC20) as well as maximum surface excess (Γmax) and minimum surface area (Amin). The measurements of the gemini compounds gave low CMC, high efficiency in reducing the surface tension, and intense adsorption at air/water interface. These surfactants have lower Krafft points and thus better solubility. Thermodynamic data, free energy, entropy, and enthalpy changes (ΔG°, ΔS°, and ΔH°) for micellization at the air/water interface and also for adsorption in the bulk of surface-active solutions were calculated. GRAPHICAL ABSTRACT

Effect of gemini surfactant additives on pour point depressant of crude oil

ABSTRACT Efficiencies of cationic gemini surfactant additives in improving the pour point depressant of crude oil were investigated. The length of alkyl chain is a major factor affecting the improvement of the pour point depression. The adsorption behavior of these gemini surfactants at air/solution and oil/solution interfaces were investigated by measuring the surface tension and interfacial tension as functions of concentration. It is found that there is a good relation between surface properties especially interfacial tension of the gemini surfactants and their efficiency in depressing the pour point. Also, the surface parameters and free energies of micellization and adsorption confirm the decreasing and improving of pour point depression. Crystallization study in crude oil revealed the relationship between the structure and activity of gemini surfactant additives. It is found that the x-ray diffraction patterns of waxes with additives are remarkably different from those without additives. The mechanism of the depressants action has been suggested according the adsorption of each additive. Adsorption of the additive on the surface of the wax particles inhibits their growth and alters the crystal habits through micelle core. Pretreatment of the crude oil with pour point depressants has received the greatest acceptance due to its simplicity and economy. GRAPHICAL ABSTRACT

Role of Surfactants in Regulation of Cancer Growth

Introduction: A brief review is presented in the field of petroleum carcinogenesis. Epidemiological surveys in occupationally exposed populations postulate that long exposure to polycyclic aromatic hydrocarbons (PAHs) is carcinogenic. Several novel surfactants were investigated by Badawi and his collaborators on regulation of cancer growth. Other investigators recorded the role of cationic surfactants and pegylation.

Surface Parameters, Biodegradability, and Antimicrobial Activity of Some Trisodium N-acyl ED3A Surfactants

A new kind of surfactant with chelating properties named N-acyl ethylenediamine triacetate (N-acyl ED3A) of different hydrocarbon chain lengths was synthesized from anhydrous ethylene diamine, fatty acid chlorides (capryloyl, lauroyl, myristoyl, palmitoyl, stearoyl, or oleoyl chloride) and chloroacetic acid. Surface parameters and thermodynamic parameters were investigated. The prepared surfactants were tested for their biodegradability and their antimicrobial activity against different strains of bacteria, yeast, and fungi was investigated.