Surfactants and Interfacial Phenomena

Rosen, Milton J.; Kunjappu, Joy T.

doi:10.1002/9781118228920

Cited by 1,739 publications

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“…The effectiveness of these mixtures (γ cmc ) is similar to those reported for surfactants with comparable hydrophobic groups [29]. However, the C 20 is significantly low.…”

Section: Critical Micelle Concentration Of the Surfactant Mixturessupporting

confidence: 67%

“…As expected, surfactants with longer alkyl chains gave rise to lower cmc values due to their superior hydrophobicity. This behaviour is analogous to that described for different surfactant families [29,31,32]. Finally, analysing the effect of salt removal, Table 2 shows that the cmc values decreased in surfactant mixtures without salts ( Figure 4).…”

Section: Critical Micelle Concentration Of the Surfactant Mixturesmentioning

confidence: 52%

“…The lower the cmc the more efficient the surfactant as foaming agent [29], consequently, the foaming capacity enhances by increasing the length of the hydrophobic group of the surfactant. This trend has been also confirmed for surfactant mixtures obtained from acylated peptides.…”

Section: Foaming Propertiesmentioning

confidence: 99%

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Valorization of tannery wastes: Lipoamino acid surfactant mixtures from the protein fraction of process wastewater

Bautista

Pérez

Garcı́a

et al. 2015

Chemical Engineering Journal

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The first stages of the transformation process of hides into leather (beamhouse process) generate an important waste in the tanning industry, since a considerable fraction of solubilised proteins ends up in waste water with the corresponding increase in contamination parameters, especially when the process is carried out without hair recovery (hair-pulping process). The objective of this work was the valorisation of this waste (the separated protein fraction) which conveniently hydrolyzed to amino acid level constituted the starting material for the production of biodegradable surfactants.The lipoamino acid surfactants were obtained by acylation of the amino acids from the protein hydrolisate. These surfactants were characterized and their physico-chemical and biological properties evaluated. They exhibit very low cmc values (about 40 mg/L).These surfactants are readily biodegradable and present an aquatic toxicity significantly lower than many common commercial surfactants derived whether from renewable or petrochemical feedstock. The mixtures of surfactants obtained are able to form oil/water emulsions that remain stable for at least one year. The results obtained in this work confirmed that it is possible the production of biodegradable and efficient lipoamino acid surfactant mixtures from the protein fraction present in beamhouse process wastewaters. This study constitutes a promising approach for the reduction of the pollution load from industrial tannery wastes and its valorisation as raw material for the production of surfactants with excellent environmental properties and good technical properties.

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“…The effectiveness of these mixtures (γ cmc ) is similar to those reported for surfactants with comparable hydrophobic groups [29]. However, the C 20 is significantly low.…”

Section: Critical Micelle Concentration Of the Surfactant Mixturessupporting

confidence: 67%

Section: Critical Micelle Concentration Of the Surfactant Mixturesmentioning

confidence: 52%

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Valorization of tannery wastes: Lipoamino acid surfactant mixtures from the protein fraction of process wastewater

Bautista

Pérez

Garcı́a

et al. 2015

Chemical Engineering Journal

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“…1,2 These are remarkably versatile compounds with a broad variety of important applications in the pharmaceutical, medical, and food industries and for nanomaterial synthesis. 3,4 Above a certain temperature in solution (the Krafft temperature), surfactants tend to aggregate to minimize unfavorable interactions between the surfactants and the surrounding environment.…”

Section: Introductionmentioning

confidence: 99%

“…16,17 Computational simulations have also been employed to explore the structures and dynamical behaviors of micelles for different surfactants. 18 Considering that no holes exist within a micelle, its radius is estimated as the maximum extension of a hydrocarbon chain and can be evaluated by using the following equation: l max = 0.15 + 0.1265n C (1) where l max is the maximum length in nm and n C is the number of carbon atoms in the chain. 19 Indeed, under the previously mentioned conditions, l max plus the length of the polar group is approximately equal to the radius of the spherical micelles.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of Cetyltrimethylammonium Bromide (CTAB) Micelles and their Interactions with a Gold Surface in Aqueous Solution

Silva¹,

Dias²,

Hora³

et al. 2017

J. Braz. Chem. Soc.

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Surfactants are molecular structures with remarkable physicochemical properties and applications. Most of their characteristics are due to their ability to promote aggregation and interactions with different interfaces. The scarcity of theoretical studies dedicated to evaluating the forces involved in these interactions prompted us to propose other models capable of reproducing the experimental data in better ways. We carried out molecular dynamics (MD) simulations to obtain a model for cetyltrimethylammonium bromide (CTAB), selected from gromos54a7 force field parameters, that better describes most of its behaviors in aqueous solution (micellar structure, counterion dissociation, etc.) and its adsorption pattern on a gold surface. The parameters adopted for one of the models were able to mimic several characteristics suggested by experimental measurements of the CTAB micelles, as well their adsorption pattern on a gold surface. Indeed, this model was able to obtain quasi-spherical micelles, as well as a pattern of adjacent cylindrical micelles with alkyl chain interactions on a gold surface.Keywords: molecular dynamics, micelles, interface interaction, cetyltrimethylammonium bromide, gold IntroductionSurfactants are a class of compounds containing a polar group, charged or neutral, attached to a long hydrophobic tail.1,2 These are remarkably versatile compounds with a broad variety of important applications in the pharmaceutical, medical, and food industries and for nanomaterial synthesis.3,4 Above a certain temperature in solution (the Krafft temperature), surfactants tend to aggregate to minimize unfavorable interactions between the surfactants and the surrounding environment. 5 The minimum concentration required for surfactant aggregation is defined as the critical micellar concentration (CMC), and most of the characteristics of these aggregates are controlled by factors such as the solvent type, chemical structure of the surfactant, and solution conditions (e.g., concentration, temperature, presence of additives, and ionic strength). 6Variations of these factors yield aggregates with different morphologies such as spherical or ellipsoidal micelles, cylindrical or thread-like micelles, disk-like micelle, membranes and vesicles.7 These self-assembled structures have been characterized by a number of techniques, such as dynamic light scattering (DLS), 8 nuclear magnetic resonance (NMR), 9,10 fluorescence spectroscopy, 11 quasielastic neutron scattering (QENS), 12,13 small-angle X-ray scattering (SAXS), 14,15 and small-angle neutron scattering (SANS). 16,17 Computational simulations have also been employed to explore the structures and dynamical behaviors of micelles for different surfactants. 18Considering that no holes exist within a micelle, its radius is estimated as the maximum extension of a hydrocarbon chain and can be evaluated by using the following equation:where l max is the maximum length in nm and n C is the number of carbon atoms in the chain. 19 Indeed, under the previously mentioned conditions, ...

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Foams

Saint-James¹,

Durian²,

Weitz³

et al. 2012

Kirk-Othmer Encyclopedia of Chemical Technology

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Foam is a nonequilibrium dispersion of gas bubbles in a relatively smaller volume of liquid containing surface‐active molecules. Foams that are relatively stable can be thought of as a form of condensed matter both solid‐like in being able to resist shear elasticity, and liquid‐like in being able to flow and deform into arbitrary shapes. The extent to which macroscopic stability and rheology of liquid‐based foams can be understood in terms of the underlying structure and dynamics of the constituent gas bubbles and liquid films, and their ultimate origin in terms of the physical chemistry of surface‐active molecules preferentially absorbed at the gas‐liquid interfaces are reviewed. Existing measurement techniques and applications such as use in firefighting, oil recovery, cosmetics, food, separations, and detergents are discussed.

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Surfactants and Interfacial Phenomena

Cited by 1,739 publications

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Valorization of tannery wastes: Lipoamino acid surfactant mixtures from the protein fraction of process wastewater

Valorization of tannery wastes: Lipoamino acid surfactant mixtures from the protein fraction of process wastewater

Molecular Dynamics Simulations of Cetyltrimethylammonium Bromide (CTAB) Micelles and their Interactions with a Gold Surface in Aqueous Solution

Foams

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