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Surfactant use throughout mankind is extensive, from their initial applications as detergents extending to use in medicine, lubricant, cosmetics and even enhanced oil recovery. However, the image of surfactant use has in the past ...
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Surfactant use throughout mankind is extensive, from their initial applications as detergents extending to use in medicine, lubricant, cosmetics and even enhanced oil recovery. However, the image of surfactant use has in the past been tarnished by issues with low biodegradability and their synthesis from nonsustainable resources. Amino acid-based surfactants are a class of surfactants derived from a hydrophobe source coupled with simple amino acids, mixed amino acids from synthesis or from protein hydrolysates, and as such can be derived solely from renewable resources. There are several pathways for their synthesis and this allows for extensive structural diversity in this class of surfactants, resulting in widespread tuneable functionality in their physiochemical properties. This review includes the details of most of the available routes of synthesis for amino acid surfactants (AASs) and the impact of the diverse routes on their final physiochemical properties, including solubility, dispersability, toxicity and biodegradability. The diversity offered by the structural variation in AASs offers many exciting commercial opportunities for this ever-growing class of surfactants. It also includes a discussion on current and future potential uses of AASs. (C) 2017 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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In this brief overview of a large and complex subject, as presented at the 2018 Surfactants in Solution conference, the need for, and impact of, hard surface antimicrobial products is demonstrated. The composition of the interface...
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In this brief overview of a large and complex subject, as presented at the 2018 Surfactants in Solution conference, the need for, and impact of, hard surface antimicrobial products is demonstrated. The composition of the interfaces of three common classes of pathological microbes, bacteria, viruses, and fungi, is discussed so that surfactant and cleaning product development scientists better understand their interfacial characteristics. Studies of antimicrobial efficacy from the four major classes of surfactants (cationic, anionic, amphoteric, and nonionic) are shown. The need for preservatives in surfactants is elucidated. The regulatory aspects of antimicrobials in cleaning products to make antimicrobial claims are stressed.
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Dimeric (gemini)surfactants are made up of two amphiphilic moieties connected at the level of, or very close to, the head groups by a spacer group of varying nature: hydrophilic or hydrophobic , rigid or floxible . These surfactan...
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Dimeric (gemini)surfactants are made up of two amphiphilic moieties connected at the level of, or very close to, the head groups by a spacer group of varying nature: hydrophilic or hydrophobic , rigid or floxible . These surfactants represent a new class of surfactants that is finding its way into surfactant-based formulations.The nature of shown to be of the utmost importance in determining the solution properties of aqueous dimeric surfactants.This paper reviews the effect of the nature of the spacer on some of these properties.The behavior of dimeric surfactants in the submicellar range of concentration, at interfaces, in dilute solution (solubility in water, Krafft temperature, critical micellization concentration, thermodynamics of micelle formation , micelle ionization degree , size, polydispersity, micropolarity and microviscosity , microstructure and rheology of the solutions, solubilization , micelle dynamics , and interaction with polymers) and in concentrated solution (phase behavior) are successively reviewed .Selected results concerning trimeric and tetrameric surfactants are also reviewed
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The electrical-double-layer (EDL)-based adsorption models for ionic surfactants propose all surfactant heads ideally aligned in the Stern layer, creating a single surface potential which controls the distribution of counterions wi...
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The electrical-double-layer (EDL)-based adsorption models for ionic surfactants propose all surfactant heads ideally aligned in the Stern layer, creating a single surface potential which controls the distribution of counterions within the diffuse layer. Despite their successful application to many surfactant systems, these models exhibit a noticeable shortcoming when it comes to explaining the larger surface excess of ionic surfactants at air vertical bar water interface than oil vertical bar water interface. Experiments and computation simulations have already shown that some surfactant head groups tend to immerse into the deeper layers of interfacial water at high surface coverage. Such an immersion alters the surface potential distribution and characteristics of EDL. However, a theoretical study of this phenomenon is not available yet. This paper presents a useful modeling approach to quantification of the surfactant immersion. We combined the ionic surfactant adsorption models with the theory of equilibrium adsorption constant. We modified several non-ionic surfactant adsorption models for describing the ionic surfactant adsorption by accounting for their immersion. The adsorption parameters were determined by fitting to experimental adsorption data and were then used along with the theory of equilibrium adsorption constants to successfully explain the reported difference in the surface excess of sodium dodecyl sulphate (SDS) at air vertical bar water and oil vertical bar water interfaces. The surfactant immersion directly affected the intermolecular interaction parameter which was closely related with the adsorption energy of surfactants at the interfaces. The collaborative effect of these two parameters was also found to be responsible for the immersion of surfactants and shaping their different concentration profiles across various liquid vertical bar fluid interfaces. The immersion of surfactants was found to enhance their surface adsorption effectively. Also, our model successfully elucidated why SDS adsorption at the oil vertical bar water interface unexpectedly decreases as the hydrophobicity of the oil phase increases. (C) 2016 Elsevier B.V. All rights reserved.
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We report a chemodegradable surfactant system based on oxidation of Br-N+(CH3)(3)(CH2)(8)SS(CH2)(8)N+(CH3)(3)Br- (1) to N+(CH3)(3)(CH2)(8)SO3- (2) by addition of sodium hypochlorite (NaOCl). Prior to oxidation, the interfacial pro...
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We report a chemodegradable surfactant system based on oxidation of Br-N+(CH3)(3)(CH2)(8)SS(CH2)(8)N+(CH3)(3)Br- (1) to N+(CH3)(3)(CH2)(8)SO3- (2) by addition of sodium hypochlorite (NaOCl). Prior to oxidation, the interfacial properties of aqueous solutions of 1 (critical micelle concentration similar to 1 mN/m and limiting surface tension similar to 45 mN/m) are similar to those of Br-N+(CH3)(3)(CH2)(16)N+(CH3)(3)Br- (3), demonstrating that introduction of the disulfide bond into the surfactant structure does not substantially change its surface-active properties. The surface tensions of aqueous solutions of 1 were found to increase by up to 26 mN/m upon addition of NaOCl. These changes in surface tension were measured within similar to 2-3 min of the addition of a stoichiometric ratio of NaOCl to 1 of 6:1 at 25 degrees C. The oxidation of 1 to 2 can also be effected over a wide range of pH (3 < pH < 11) and by using commercial formulations of bleach. The volume of bleach necessary to oxidize a 2 mM solution of 1 was less than 2.5% of the total volume of the solution. We demonstrate, in addition, that oil-in-water emulsions formed from 5 wt % dodecane in a 10 mM aqueous solution of 1 are visually stable over 24 h but can be disrupted (within similar to 10 min) upon addition of NaOCl (6:1 stoichiometric ratio of NaOCl to 1). [References: 37]
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A novel gel phase was constructed in a catanionic surfactant system with the compositions of 1-tetradecyl-3-methylimidazolium chloride (C(14)mimCl) and sodium dodecyl sulfate (SDS). The gel phases were studied through visual obser...
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A novel gel phase was constructed in a catanionic surfactant system with the compositions of 1-tetradecyl-3-methylimidazolium chloride (C(14)mimCl) and sodium dodecyl sulfate (SDS). The gel phases were studied through visual observations, differential scanning calorimetry (DSC), rheological measurements, and scanning electron microscopy (SEM). The visual observation and DSC confirmed the formation of gels and phase transitions from gel to sol. The dynamic rheological results showed the viscoelastic properties of gels. The SEM technique was used to further indicate the microstructure of gels. Finally, the formation mechanisms of gels are proposed based on the critical packing parameter. We expect to develop a new route to construct the gels.
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A novel homologous series of trimeric anionic surfactants, 3C (n) TE3CNa (where n is a fatty acid chain length of 7, 10, or 12), with three hydrocarbon chains and three carboxylate heads connected via tri-etheric bonds were synthe...
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A novel homologous series of trimeric anionic surfactants, 3C (n) TE3CNa (where n is a fatty acid chain length of 7, 10, or 12), with three hydrocarbon chains and three carboxylate heads connected via tri-etheric bonds were synthesized from long-chain alpha-bromo fatty acids and a triol, 1,1,1-tris(hydroxymethyl)ethane. The obtained trimeric carboxylic acids were esterified and purified by silica gel column chromatography, then hydrolyzed with dilute sodium hydroxide solution to form a series of trimeric carboxylate surfactant products. All prepared compounds were analyzed by IR, H-1 NMR, and C-13 NMR spectroscopy to confirm their chemical structures. Their surface-active properties were investigated. The critical micelle concentrations (cmc) of 3C (n) TE3CNa were in the range of 0.12-0.71 mmol/L, and the surface tensions at the cmc (gamma (cmc)) were 29.3-34.8 mN/m.
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An overview of surfactant-amino acid interactions mainly in aqueous medium has been discussed. Main emphasis has been on the solution thermodynamics and solute-solvent interactions. Almost all available data on the topic has been ...
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An overview of surfactant-amino acid interactions mainly in aqueous medium has been discussed. Main emphasis has been on the solution thermodynamics and solute-solvent interactions. Almost all available data on the topic has been presented in a lucid and simple way. Conventional surfactants have been discussed as amphiphiles forming micelles and amino acids as additives and their effect on the various physicochemical properties of these conventional surfactants. Surfactant-surfactant interactions in aqueous medium, various mixed surfactant models, are also highlighted to assess their interactions in aqueous medium. Finally, their applied part has been taken into consideration to interpret their possible uses.
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The surfactant structure-performance relationship and application properties in enhanced oil recovery (EOR) for binary mixtures of anionic and cationic surfactants are presented and discussed. A polyoxyethylene ether carboxylate a...
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The surfactant structure-performance relationship and application properties in enhanced oil recovery (EOR) for binary mixtures of anionic and cationic surfactants are presented and discussed. A polyoxyethylene ether carboxylate anionic surfactant was blended with a quaternary ammonium chloride cationic surfactant and tested for a high-temperature, low-salinity, and high-hardness condition as found in an oil reservoir. These mixtures were tailored by phase behavior tests to form optimal microemulsions with normal octane (n-C8) and crude oil having an API gravity of 48.05A degrees. The ethoxy number of the polyoxyethylene carboxylate anionic surfactant and the chain length of the cationic surfactant were tuned to find an optimal surfactant blend. Interfacial tensions with n-C8 and with crude oil were measured. Synergism between anionic and cationic surfactants was indicated by surface tension measurement, CMC determination, calculation of surface excess concentrations and area per molecule of individual surfactants and their mixtures. Molecular interactions of anionic and cationic surfactants in mixed monolayers and aggregates were calculated by using regular solution theory to find molecular interaction parameters beta (sigma) and beta (M) . Morphologies of surfactant solutions were studied by cryogenic TEM. The use of binary mixtures of anionic/cationic surfactants significantly broadens the scope of application for conventional chemical EOR methods.
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It is our pleasure and honor to commemorate Dr. Milton J. Rosen by publishing this special issue to recognize his contributions and accomplishments in surfactant science and applications. Dr. Rosen had been a mentor and a colleagu...
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It is our pleasure and honor to commemorate Dr. Milton J. Rosen by publishing this special issue to recognize his contributions and accomplishments in surfactant science and applications. Dr. Rosen had been a mentor and a colleague to many former students, visiting scholars, and scientists from academia and industry over the years. This paper provides an overview of his professional and personal life and his impact on the field of surfactant science and technology and on the American Oil Chemists' Society.
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