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Berberich, K. A.; Reinsborough, Vincent C.; Shaw, C. N.

doi:10.1023/a:1005194903146

Cited by 13 publications

(2 citation statements)

References 6 publications

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“…The use of nonionic or cationic surfactants causes inhibition of the complexation . Reinsborough et al investigated the influence of the addition of cations on the catalytic effect produced by micelles, as well as the influence of the micellar structure and the effect exerted by zwitterionic surfactant solutions . The studies on micellar systems were extended using fluorate surfactants and mixtures of surfactants and included the effect exerted by additives such as alcohols and ureas on micellization .…”

Section: Introductionmentioning

confidence: 99%

Metal−Ligand Complexation in Water-in-Oil Microemulsions. I. Thermodynamic Approach

Fernández¹,

García‐Río²,

Knörl³

et al. 2003

Langmuir

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The complexation constants of Ni 2+ and Co 2+ with pyridine-2-azo-p-dimethylaniline (PADA) were determined in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane/water microemulsions at 25 °C. The results show that the complexation constants depend on the microemulsion composition. In all cases, the values of the apparent complexation constants are greater than those obtained in bulk water. To carry out a quantitative interpretation of the experimental results, we propose a complexation scheme that considers the microheterogeneous character of the microemulsion. It was found that the PADA is distributed between the continuous medium and the interface of the latter, whereas the Ni 2+ or Co 2+ ions are distributed between the aqueous microdroplet and the interface. If we consider an ionic exchange equilibrium between the counterion (Na + ) of the AOT and the reactive cation (Ni 2+ or Co 2+ ), it is possible to obtain the true complexation constants at the interface of the microemulsion. The values obtained for the true complexation constants decrease as the water content of the microemulsion increases and are always lower than the values obtained in bulk water. The interaction of interfacial water with the surfactant headgroup in the microemulsion causes an increase in the electronic density on the oxygen atoms of water and a consequent increase in the interaction H 2O‚‚‚M 2+ , which in turn leads to a greater stabilization of the ion with respect to that in bulk water. As the water content decreases, this interaction becomes stronger but the quantity of water molecules available for hydration decreases. This situation results in destabilization of the ion and an increase in its complexation capacity.

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Section: Introductionmentioning

confidence: 99%

Metal−Ligand Complexation in Water-in-Oil Microemulsions. I. Thermodynamic Approach

Fernández¹,

García‐Río²,

Knörl³

et al. 2003

Langmuir

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show abstract

“…To obtain the best enhancement effect, negatively charged reactors (SDS) are used for positively charged metal ions (for instance, Cd 2+ or Ni 2+ ) [75]; however, since the metal center may be present as a negative species [76,87], conversely, a positive micelle (e.g., DTAC) becomes the best choice. The "catalytic effect" was also found to occur for the Ni 2+ /PADA system in the presence of zwitterionic micelles formed with carboxybetaines; nevertheless, it does not occur for zwitterionic micelles by sulfobetaines because metal ions are not appreciably adsorbed by them [96]. The effect may also be lost if the species are compartmentalized in different parts of the amphiphilic system: again, if the ligand is highly hydrophobic it may be preferentially located in the core of the micelle, far from the surface.…”

Section: Metal Complexes Speciation In Amphiphilic Mediamentioning

confidence: 93%

Quantitative Analysis of the Interactions of Metal Complexes and Amphiphilic Systems: Calorimetric, Spectroscopic and Theoretical Aspects

et al. 2022

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Metals and metal-based compounds have many implications in biological systems. They are involved in cellular functions, employed in the formation of metal-based drugs and present as pollutants in aqueous systems, with toxic effects for living organisms. Amphiphilic molecules also play important roles in the above bio-related fields as models of membranes, nanocarriers for drug delivery and bioremediating agents. Despite the interest in complex systems involving both metal species and surfactant aggregates, there is still insufficient knowledge regarding the quantitative aspects at the basis of their binding interactions, which are crucial for extensive comprehension of their behavior in solution. Only a few papers have reported quantitative analyses of the thermodynamic, kinetic, speciation and binding features of metal-based compounds and amphiphilic aggregates, and no literature review has yet addressed the quantitative study of these complexes. Here, we summarize and critically discuss the recent contributions to the quantitative investigation of the interactions of metal-based systems with assemblies made of amphiphilic molecules by calorimetric, spectrophotometric and computational techniques, emphasizing the unique picture and parameters that such an analytical approach may provide, to support a deep understanding and beneficial use of these systems for several applications.

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Properties and applications of amphoteric surfactant: A concise review

Sarkar

Pal

Rakshit

et al. 2021

J Surfact & Detergents

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Amphoteric surfactants have long hydrophobic hydrocarbon chain and hydrophilic positive as well as negative charged center connected with each other by a spacer group. Thus, this type of surfactant maintains overall charged neutrality. The properties of amphoteric surfactants depend primarily on the length of the hydrophobic hydrocarbon chain, the number of methylene segments in the spacer, the positive and negative charged groups, and their relative position. The ionic activity of amphoteric surfactants is influenced according to the pH value of the solvent. They display cationic behavior below the isoelectric points and anionic behavior at a higher pH. They take the shape of zwitterions in the area of the isoelectric point. In fact, amphoteric surfactants can be parted into pH‐sensitive and pH‐insensitive surfactants. The pH‐insensitive surfactants stay as zwitterionic form irrespective of the pH of the solution. This surfactant has some unique features because of its precise molecular structure as follows: high water solubility, high surface activities, a wide isoelectric range, low critical micelle concentration (CMC), high foam stability, low toxicity, low irritating, excellent biodegradability, bioactivity, interface change, and so on. Because of these special characteristics, amphoteric surfactants have been immensely interested in many applications in the scientific community, including cosmetics, chromatography, enhanced oil recovery, electrochemistry, nanoscience, polymer chemistry, and waste water treatment. This review aims to study about amphoteric surfactants, which have only one hydrophobic hydrocarbon tail and two oppositely charged hydrophilic headgroups connected with each other by a spacer group and its properties, applications in various academics and industrial fields.

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Untitled

Cited by 13 publications

References 6 publications

Metal−Ligand Complexation in Water-in-Oil Microemulsions. I. Thermodynamic Approach

Metal−Ligand Complexation in Water-in-Oil Microemulsions. I. Thermodynamic Approach

Quantitative Analysis of the Interactions of Metal Complexes and Amphiphilic Systems: Calorimetric, Spectroscopic and Theoretical Aspects

Properties and applications of amphoteric surfactant: A concise review

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